Incidently...
Plug and Play...
If you switch this off in the bios this can help to prevent this and similar problems.
Plug and Play is where the bios tries to allocate hardware resources it finds in best manner appropriate. This can be a good thing but the downside is that if your situation is constantly changing like a dodgy connection to a slave drive etc the whole config of the computer changes and the bios and windows can get its knickers in a twist big time.
Whilst plug and play is a great concept - it has never really worked well and is best switched off.
Cheers