If you go into Control Panel, in the top right corner change view to small icons. Find Default Programs. Click the second option, Associate a file type or protocol with a program. There, you can change your file associations back. Find XLS, XLSX, DOC, DOCX, PDF, JPG in the list of file extensions, and re-associate them with the appropriate programs.
However, if you have a virus, make sure that is completely eradicated from your system first. Often times, it is difficult to know for sure that you have eliminated all traces of the virus from your PC. If you're not sure, then the best course of action is to format your hard drive and reinstall Windows from the CD. That is the only way to know for sure that your computer is clean.
01-29-2015 07:59 AM