Cannot Perform System Restore

It was fine til her son installed some regular computer games you buy in a store. Then suddenly when she double clicked her desktop icons to open them instead of opening a program they would create a shortcut on the desktop though duplicating her icons. Also her mouse was making her text smaller and bigger without her having it do so. She also told me that when she was in firefox it would suddenly open up many tabs without her asking it to of the same thing. She tried to do a system restore to an earlier time but it wouldnt even let her go to the calendar to pick a date. She called me to find out if I knew anything. I got her to boot her computer in Safe Mode and run a virus scan which found nothing. To me it sounds like some sort of malware or spyware but not sure. Do you have any ideas other then reformatting the pc which is what I think her husband will end up doing unless I can find another answer.