The main problem I'm having right now is that whenever I try to open a program a dialogue box comes up asking me which program I want to use to open it with and that's a problem because not all of the programs are in the list or can be found by browsing - particularly Windows Update and System Restore. (I'm not sure if either of these things would help... already tried Restore and did nothing, besides I have no idea when to go back to.)

I'm pretty sure the problem has to do with all the viruses my computer was loaded with but appear to have stopped messing everything up. I got rid of them with Windows Defender and McAfee, but deleted McAfee because it slows stuff down, so also wondering what I should get in place of McAfee.

Also, running Vista.