I seem to have no problem with my Windows Live Messenger at all. ( and to the other user, WLM happens to be one of the best IM's there are) It must be something from your own computer that's hurting your WLM. Do you have a good anti-virus program? If you have one, make sure it's activated, or that it's license hasn't expired or anything. If you don't have one, or are looking for one, Windows Live OneCare does a pretty great job of doing so, and it's really easy to work with and has a great UI to go on : http://onecare.live.com/standard/en-us/default.htm
Otherwise than that, just reinstall WLM on your computer, and hopefully it will work better this time. Just make sure that if you download any free downloads on the internet, it could have viruses, or something that could harm your computer on it. Hopefully you haven't done any of those free downloads stuff on your WLM, cause it might be the cause of it. WLM has it's own page for certified downloads for your messenger right here: http://gallery.live.com/results.aspx?c=36&bt=2&pl=3 But you'll only find 50, and that's including both IM and Mail.
On a side note, have you heard of this neat thing, where you can help save the world, just by IM'ing? Windows Live Messenger also has this official thing on their site about how by just doing this quik and easy set-up, anytime you IM a friend, a portion of the ad revenues goes to an organization of your choice (from a list of 9) and from there, you can download neat stuff for your WLM to show your cause. Here's the link: http://im.live.com/Messenger/IM/Home/
Good luck. Hope this helps. E-mail me on my profile if you need more help.