Display problems

I recently changed my PC from XP to W7, and I'm liking the change. However I've been having some minor problems and I can't figure out how to fix them.

Problem 1:
Every time I try to open up my MSN Messenger, the bottom half of the box is completely black so I can't see anything. I can't seem to find a fix for it.

 Spoiler

Problem 2:
After anywhere from 30 minutes to 2 hours, my desktop background changes from the picture I have to a solid black color. It's not set to slide show or anything like that. I saved the picture to my documents before setting it as my background too.

If anyone knows any fixes, it'd be greatly appreciated.

I used to have the same problem, let me ask you though..are you using a "trial" version of 7 or something similar? Anything that isnt a full on legitimately purchased copy?

weird, i used to have that msn problems long time ago, but only while running maple.

i somehow fixed it updating my nvidia graphics card and installing net framework 3.5.

about the background, it seems like the win7 aero stop working, do you get any msg when the background turn into a solid color? iTunes used to do it with my win7 background back then, and to fix it i installed the 64bits version of itunes(my win7 is 64bits).