What is the error message? Are you trying to log in to a normal User Account in Safe Mode or to the Administrator account?
The w32/blaster problem has now changed to an error on the disk which is an entirely different problem.
The error that occured on safe boot was that the system stopped and said that a virus in the system has caused a failure or that I should run chkdsk /f to try to find the error. I did run chkdsk but no problem was found.
I did however bring the systen up in normal mode and signed in under guest which was ok. I ran all the virus removal software and all was ok for over 24 hours until the disk error occured and stopped the system. Will have to start from scratch now.
There is malware that tells you there's a disk error - sure it isn't that? It usually asks for money to fix it. I doubt your malware scans were very effective in a Guest account. Try the Administrator in Safe Mode if there's any doubt.