Sit down and get comfortable. You are having a problem with you boot sequence and having the 3rd party boot loader is only making it worse.
First, logon to Ubunto and save all of you stuff to an external drive. You want to do this to make sure you don’t loss any of your files during this process.
After that’s dune (don’t restart just yet) insert the windows CD and restart your computer. When prompted to hit any key to boot from the CD, do so. After the windows setup loads (the blue screen) hit “R” to repair the computer using the recovery consol. Be sure not to install the recovery consol (it’s a very useful tool, but can be annoying to have as one of your boot options). Once the repair consol loads, you will be prompted to chose witch windows installation that you want to repair (usually #1) then you need to enter your password (if you made one for windows). Now that you’re in the RC, you will need to rewrite your boot sector and rebuild the windows boot loader. To do that you will need to enter in a few commands in the command prompt.
I’m not exactly sure what the names of the commands are but if you type “help” you will get a list of commands. The first one is (I think) fixmbs (or fixmbr) witch will rewrite the boot sector. The next command is fixboot witch will rebuild the boot.ini file. Restart the computer by typing exit.
Now that you have the windows boot loader in place and working, you can use one of Windows built in little helpers. Its called the last know good configuration. To use this, hit the F8 key repeatedly while the computer first starts. This will put you in the advanced start options menu. Down on the bottom of the list, there will be the last know good configuration. Select it and hit enter. This should get you into Windows. If that doesn’t work, then perform a system restore in the same menu select recover using system restore. That will let you go back to the last system restore point.
If all ells fails, use your Ubunto disk to get into Ubunto, save all of your windows doc’s to an external hard drive and reinstall Windows.
GOOD LUCK!!