Special Keys Wouldn't Work Properly, Internet Explorer Would Crash, PDF Files Wouldn't Open, Etc

I was fixing a laptop that was having several issues, (special keys wouldn't work properly, internet explorer would crash, PDF files wouldn't open, etc) and I found a suspicious file (C:User<user>AppDataRoamingElofenmoma.exe) that was booting on startup. Virustotal hit me with only 3 results for a trojan, which is actually quite low, but this file was clearly the problem, the details seemed to be in russian and it's Regedit entry was random letters.

So I cleaned all evidence of this file and now the keyboard works properly, but I'm still having problems with executable. Most of the times when I open a program nothing shows up, yet the process is running, after opening it 3 or 4 times one window finally opens, but there's still 3 or 4 idle processes before it with no window in sight. Some times when I force close the first process all the other windows suddenly show up. I also noticed that the processes for setups, chrome, internet explorer tend to stay idle even after closing them normally (in the program itself, manually closing the process works).Usually I would just format the PC, but this is a very complicated PC to format, the owner has tons of certificates that he needs and most of them he doesn't even remember how to reinstall them again.