Problems Opening Files/Programs

So apparently I had a massive amount of viruses on my computer, of which I recently purchased Vista anti-virus to remove them all. This worked great for a bit but now whenever I try opening any program/file it asks me which program I want to use to open it. This includes .exe files, along with things like IE, iTunes. Windows Media Player, and many others. I have downloaded a patch that is supposed to fix this, but when I go to open the file (which is a .exe one) it once again asks me which program I want to open it with. Can anyone help me out here as I am kinda freaking out about this all.
TIA
Ryan

Welcome

Sorry that you are having problems.

Maybe this will help

http://www.vistax64.com/tutorials/83196-default-programs-program-default-associations.html

Unfortunatly my issues go much deeper then that. When I even try to open some programs such as Internet Explorer, iTunes, and quite a few others, the "Open With" window pops up, and I have to select which program I want to open these with. In most cases I just have to find the ".exe" file of the program under the "Program Files" folder, but this does not always work. It's happening to the point that whenever I try to open a new tab in IE the "Open With" window pops up and I once again have to hunt down the "iexplorer.exe" file and select it. The box to click "always open with this program" is showing, but I can't click on it. I'm really trying to not have to reinstall windows so any help would be extremely useful.
Ryan

Sorry that you are still having problems, Ryan.

Maybe this will help.

Go to start, type cmd, do not hit enter, right click and run as administrator.

In the cmd prompt type sfc /scannow.

Well I tried that and still having the problem. I've been doing some research and it seems this was also a common problem with XP. I'm hoping to find out at least what caused this to happen, if for nothing else so I can at elast make sure it doesn't happen again.
Ryan