Your virtual memory can run low for a couple of reasons:
1) You don't have enough memory installed for your operating system and/or the software you are using, especially using many programs at once.
2) The "swap file" is not set large enough.
3) Your disk is horribly fragmented.
4) You have too many fonts installed.
Though turning off your computer will *surely* clean the virutal memory, it will just fill up again -- I'm sure you don't want to continue having problems completing tasks you are doing!
First, I will explain how the above can cause the problem:
1 -- Low Memory) Microsoft advertises memory requirements lower than what Windows actually needs. What they call "mininum" isn't high enough, not if you think that should preclude causing crashes and freezes or virtual memory full errors! Whatever they say is the "recommended" is *really minimum* for multi-tasking. For real productivity, you should have *twice as much as the "recommended"*.
For XP, I say you should have at least 512MB of memory. You can increase your memory by installing a 2nd stick the same size, or replacing with 1 larger stick, or installing 2 newer, larger sticks. A few computers *require* you use 2 sticks, and in any case, performance is better with 2 sticks.
Depending on the kind of computer you have, 2 1-GB sticks of memory will only cost you $190. 512MB is much less. Go to http://www.cdw.com and they know exactly what brand and speed of memory your computer uses and whether you need 2 sticks or not. 2 is better, anyway.
2 -- Swap File not Optimal Size) Windows uses a "swap file" to move data in and out of memory, so all the data being used by software applications does not have to be in memory all at once. It literally writes the contents of memory, in chunks called "pages" to your hard drive as needed. If the swap file is too small for the amount of memory you have, there is excess disk reading-writing and that slows down your system. Linux uses a different technology, but the idea in general is called "Virtual Memory".
You did not post any details about the size of your hard disk, your memory type and size, or your operating system or processor, so I can't give you any specifics. You could call your computer manufacturer and ask for a recommendation on what size range of "swap file" you should allow Windows to use, because you can set this.
There are dangers to setting it too large, too, and you *never* need it to be *larger* than your actual memory. Also, if you have a *lot* of memory (like 2-4 GB) there is really not any reason to even make it equal to the size of your memory. My experience with Windows is the default is never high enough with ME and XP Home, with XP Pro it was fine.
To learn the basics of computing and Windows, I recommend subscribing to "Smart Computing Magazine", which is Windows-oriented. Other mags may have more hardware reviews, but SC has more and better informational and how-to articles, including some in-depth stuff in every issue.
3 -- Disk is Fragmented) "Disk fragmentation" occurs because as you save, add to, and delete files from your hard disk (including installing and uninstalling software), it runs out of large peices of "contiguous" (uninterrupted) space, and it begins to break files and folders into pieces. They are not represented as pieces in Windows Explorer, but they are physically "fragmented" on your hard disk.
There are 2 regular maintenance tools you should use on your computer, *if you have Windows* -- "Disk Cleanup" and "Disk Defragmenter".
** Disk Cleanup **
Disk Cleanup cleans out all the temporary files and cookies that are supposed to get deleted but don't (thanks to *cough* high-quality *cough* "Win-Doze"). In fact, on ME and on XP home, DC didn't even get them all -- it only got the temporary files for "all users".
You can tell Disk Cleanup what to delete, including stuff from the Recycle Bin (make sure there's nothing there that you deleted accidentally, first, or you will not be able to restore it after doing DC). It can even compress old files (this will make them smaller, and take longer to access, but it may be worth it if stuff sits unused on your system for a long period of time. It can also delete info used by the "Content Indexer", which speeds searches. I deleted that once, and searches took a long time, so I only recommend it if you are desperate for disk space. You can even tell Windows not to Index anything in the first place. Again, this will slow searches terribly.
Depending how heavily you use your computer, you should do it once a month, or twice a month:
1) Click the "Start" button on the Taskbar.
2) In the Start menu, right-click "My Computer".
3) Click "Explore".
4) Right-click on the hard disk you want to run DC on. (Usually, "C:", where Windows is installed. If you have another hard disk for seperate storage of personal files, they will *rarely* need DC run on them.)
5) Click "Properites".
6) The Disk Properties Dialog will show information about your hard disk. Here, also, are 2 options: "Compress this drive to save space" (Will compress the whole drive, which will slow access to files, so it is rare you would want to -- I suggest leaving it *unchecked*); and "Allow Indexing Service to index this disk for fast file searching" (Should be checked by default, and I recommend it *checked*, but you could uncheck it if you're desperate...shutting it off will slow searches, especially if you have a lot of data.)
7) Click the "Disk Cleanup" button. It will tell you it is checking things and will take several minutes. Then you will see a list of what you would like Disk Cleanup to do. It will remember your selections next time, but it will always present the list to you, in case you want to change it. When you are done checking/unchecking, click "Ok", it will take a few minutes again. Here are the items in the list, with my recommendations:
* Downloaded Program Files (check)
* Temproary Internet Files (check)
* Recycle Bin (check, once you've made sure there's nothing in there that you didn't mean to delete -- double-click the Recycle Bin to see -- if there is, right-click the item in the Recycle Bin and click "Restore")
* Temporary Files (check)
* WebClient/Publisher Temporary Files (check)
* Temporary Offline Files (check)
* Offline Files (check)
* Compress old files (check if disk space is low and you have many files you don't access often)
* Catalog files for the Content Indexer (leave not checked)
Disk Cleanup, before XP Pro, I found left lots of stuff behind. If you have your folder properites set in Explorer to allow you to view system files and folders, you can check this. Run DC, then navigate down through "C:\Documents and Settings\YOUR-USER-NAME-HERE\Cookies" and see if all the cookies were cleaned out. You can also check Recent Documents and other folders, I can't list them all (like your personal temp files) because I directed my home folder to another hard disk and that changes all that stuff.
- You may have to manually delete stuff.
- If this happens to you, you can make some of the temp files and history have a lot less garbage -- to open a folder, *don't* double-click it! Instead, right-click and select "Explore". For some reason, this doesn't add all the records of your folder navigation, which will help!
** Disk Defragmenter **
This will literally move broken pieces of files around so most of them are "contiguous" (continuous) again. Again, depending on your usage, you may want to do this once every week or two, once a month, or once every few months.
Fragmented files slow down reads and writes, because the read-write head has to move all over the disk just to access 1 complete file. This affects virtual memory because the "swap file" will also be fragmented, of course. Disk Defragmenter takes longer than a few minutes (longer the lower memory you have, too).
1) Click the "Start" button on the Taskbar.
2) In the Start menu, right-click "My Computer".
3) Click "Explore".
4) Right-click the hard drive you want to Defragment (usually "C:").
5) Click "Properties".
6) Click the "Tools" tab.
7) Click the "Defragment Now" button.
8) You can click "Analyze" to just get a report and see if you *need* to defragment, but I'm sure you do the first time. It automatically analyzes, anyway, so just click "Defragment".
9) The display will constantly update. Fragmented (broken) files are red, contiguous (unbroken) files are blue, files that cannot be moved are green (this is normal to have a few unmovable files, something to do with the operating system, I'm sure).
4 -- Too many Fonts installed)
If you have hundreds of fonts, this *wickedly* slows down your system, because Windows (and all OSes as far as I know) loads them at boot.
If you buy a disk of fonts, try a few at a time, and delete what you don't like before installing more. I suggest to write down the fonts that *came with* your computer so you don't accidentally uninstall them -- doing so could cause problems with apps that need specific fonts.
Seriously, I my computer came with Windows XP Home and 128 MB of memory (definitely not adequate). Then I installed hundreds of fonts. It would take 6 minutes for Windows to load the desktop and for me to be able to actually click anything on it!