Can't download any new programs on XP


Apr 3, 2010
I have searched and when it comes back with 18000 possible, it's mind boggling. I have windows XP pro, had a virus problem, got rid of it, but I think I lost a file or something. When I try and download or open some programs I get the pop-up box "what program would you like to use?" for example, I cannot open Firefox browser, I can't download IE 8, I can't open my Olympus Picture manager. I'm sure I am missing some sort of file. Any help would be appreciated.