For weeks I have been trying to recover my PC from the effects of a virus that I downloaded. I had no antivirus software (I know). Anyway, I had a multitude of problems, the first of which was that I could not open any .exe files. I fixed that by using a registry fix that someone emailed me. I also had a "Windows could not find rundll32.exe" error on startup. I copied the file from dllcache into system32 and the error disappeared. But immediately (maybe coincidentally, I don't know) the computer started flipping out. I pulled up the process list to reveal msa.exe, b.exe. I deleted both of these manually and the PC seems to be running ok. Except for a few things which I will get to. Soon after this, I deleted the rundll32 file from system32 thinking that it had something to do with the problems.
Now, the problems I'm still having:
1) Any scan tool (Norton, HJT, Malware Bytes, whatever) does not work. Double clicking them results in nothing. I can get Norton to run by uninstalling it then re-installing it and running it upon completion of the reinstall. It scans for about 10 seconds then quits entirely. Same thing for any scan tool. It's like it knows that you are scanning for viruses and says "NO WAY, JOSE~!"
2) On one of my accounts, Firefox does not run. It says "Firefox is already running in the background but is not responding." But it is not present in the task manager.
3) I can not install Internet Explorer, no matter what version. It was damaged from the virus(es) and I wanted to re-install it.
4) After replacing the rundll file to the system32 folder thinking that it would fix the error message like last time, I get another error saying "error loading tapi.nfo."
At the end of rope. Please help. Thank you!