Whenever I try to open a program, it says "what program do you want to open this with?"?

I have asked this question before, and the answer I got worked only with windows NT or 2000, while I have a vista computer. Basically, I accidentally deleted a couple of files in my appdata/local folder, which caused my computer to not understand how to open up .exe files. This is extremely annoying and has made my computer completely worthless except for internet explorer, which is the only program that works (it's also the only program that shows up under the window where it asks what program I want to use to open up another program). The only way I can use command prompt is to plug pull and then start windows in safe mode with command prompt. I really need help and I have yet to receive an answer for this problem.