Once I had a virus. I only had the trial version of the software, so it would not fix the registry. No problem, I will just write down all those registry entries and hope I do not delete something I really need. About one-third of the way through my list, I was feeling pretty brave.
That all changed at the blink of an eye. All of a sudden, I error messages about .dlls, illegal errors and some hanky panky with memory allocation. Luckily I worked at a State agency and there was a handy place called tech support.
I went through the tech support door, carrying my sacrificial CPU, sans cords and cables. Of course, it would be Bill at the desk. He terrified all the new people, including me.
Before he could go through his whole spiel about mistreatment of computers, I stopped him. "Bill, I have written down every thing I did so you should be able to backtrack it, right?" He actually smiled at me and patted my back.
Go buy uniblue registry booster. I guarantee you will need it one or two times. But, boy, when you need it you do not time to go looking. Right now, the scan is free, the product is $39.95 with a $10 rebate, making the final cost $29.95.