XP slowdowns caused me to do full scan with my installed S&D 1.6.2.46. This found and removed 2 or 3 threats and PUP's. Then I tried to run my Personal Edition bootable CD which I bought in June 2010. I bought the CD, not an ISO download.

It goes through the "Windows is loading files..." then "Starting Windows" but then it goes BSOD, IRQL_NOT_LESS_THAN_OR_EQUAL, STOP: 0X00000004(etc....)

At the moment this is the only bluescreen I am getting.

I have certainly used this S&D Personal Edition disc in the past, but not for a long time, and probably not since my last XP re-installation which was in October 2010. My PC is old, but usually reliable, not overclocked, auto updated XP Pro SP3, Athlon XP 2500+, 2.5GB RAM, 2 SATA h/drives, 2 IDE h/drives, 2 optical drives, Tagan TG500 PSU.

I use Avast, MWBAM, SpywareBlaster and CCleaner, (but in my trusting ignorance having not read the warnings at this place, it has been my habit to use CC's Registry Cleaner whenever I do some PC 'housekeeping')

Thanks to anybody who may be able to help.