Some of my computer programs aren't opening?

I try to open some of my computer programs and I get the same message every time. The message is "(Application name) has stopped working" and it's looking for a solution. Also it says something about Microsoft client (I think that's what it is) has stopped working also. It's been doing this for a few days now and I don't know why, Here is a list of all the programs that I noticed it with. 
1. Itunes
2. Sims 3 
3. Tony Hawk Pro Skater HD
4. Sony Vegas Pro 11.0
That's all I noticed but there could also be more, does anyone know why this is doing this? Could it be virus related? I just wanna know what it is and how I can fix it.. 
Thanks, 
Also I can't uninstall Sims 3 and I was wondering could this have to do with it too? Maybe? I don't know that's why I'm asking.

Vyger4 years ago
Type in the error messages into Google search and see what it says. That is a pretty good place to start.
Sounds like your windows install my be corrupted. Could be a single file is messed up or the HDD is going bad. How old is the system. More importantly how old is the HDD?