I have XP with SP3 installed. When I switch on, the "Welcome" screen comes on as usual, then the screen goes blue and nothing further happens. No error messages. The mouse pointer shows and can be moved.
I can boot in safe mode and have backed up all data. I tried restoring to previous day then to day before that, but to no avail. The day before that I removed two viruses, Win32: Malob-KF and Hoblig-B, so I am reluctant to restore to an even earlier date. I have Avast anti-virus and it caught these in a routine boot scan. I don't know where these came from as I am careful about websites and emails; they must have somehow slipped past the real time shield. I tried scheduling another boot scan, but nothing seemd to happen in either normal or safe mode.
I have tried searching the Internet for help, but other people with a similar problem always seem to have got error messages or did not have SP1-3 installed.
Grateful for any help.