Pc help cannot run files

Hi to all, problem is when I try to install anything multiple application of the same file keeps running and the screen keeps flashing I have to close the program 20-30 times for it to stop. When I open notepad multiple instances of it keep opening. Any ideas? I tried avg if there’s any virus but came clean
Answer #1
Try malwarebytes, once installed, run through safe mode, and see if it happens there as well.
Answer #2
run hijackthis and some antivirus disks if you have some
bitdefender and avira both have virus disks that you can update and boots before windows to check for viruses.
give that a go and see if you can come up with anything,
alternatively you can try the antivirus utilities on Hiren’s Boot CD. That what I usually use now, for other computers