I got a PC that was badly infected. It would hang as it started windows.
I removed infected files from the system in my usual way: connect the HDD to an clean PC, and scan from there.
Once I restarted the customer PC using the cleaned HDD, I found stopsign popped up, wanting to scan the PC.
Sorry Stop Sign, you had your chance, and failed. I also find out that the customer had actually paid for stopsign eAcceleration
And the PC also has vet, spybot, and a few other “leftover” security software.
So I remove all old and useless security software, and install antivir, and everything starts working much better.
Remember people: don’t buy security software online, unless you are really sure it works.