I am having problems with Windows XP SP3. Operating System restarts automatically without pressing restart or Automatic Updates. Norton Security Scan-NO VIRUS (SAFE) Lavasoft Adware-Safe, Registry Cleaner-Clean.
What could be the problem and how to solve?

Have in the main cleared out a virus but cannot enable system restore. Which Registry entry do I need to remove

is there any way i could get ahold of a registry cleaner that could either find unused registries (possibly give me a date of when htey were last used) or to find known unwanted registries( virus registries etc.) it would be greatly appreciated

I’m currently experiencing a really bad virus.

First, I got a Windows Antivirus Pro, but managed to remove it and run Malwarebyte’s Anti Malware. After that, I thought it was all good, but my search results on google started redirecting to other things. Then, I got a Windows Police Pro. I removed the program files and fixed the registry so I could run programs. But there’s still something on my computer. Whenever i try to run an anti spyware or anti malware program, it halts abruptly and then I can’t open it at all. Also, my registry cleaner had the same problem. They all failed when they got to a cirtain part of the registry. AVG got through the registry without failing. I also have some suspicious processes:

msiexec.exe
mscorsvw.exe
b.exe

Also, when I was playing a game, I noticed a whole bunch of clicking sounds, as if the web browser went to another page. There was no web browser running at the time though.

Can anyone help?
Some more details:

I’ve tried SuperAntiSpyware and it won’t work. It always stops and crashes, even in safe mode.

For some reason, All my system restore points are gone.

If I login into XP the regular way, every program generates an application error of the genre "memory could not be written" or "memory could not be read".
If I login through the recovery console, this does not occur. All programs and executable work as normal.
Every virus, spyware, malware, trojan scan says the system is clean. I also ran a registry cleaner.
How do I fix this problem without formatting and reinstalling XP?