Many thanks for the reply. The AV was up to date: this happened after the laptop powered down when unplugged and the error began on restart. I can't run the AV or anything else as I can't access windows or dos. I've done a system restore, restore to last known working settings, and if I try to boot in safe mode I get the same error. I think I am going to have to reinstall windows but I need to get the files off the hard drive. I tried non-destructive system recovery and it didn't work. I've tried connecting the laptop to my desktop via USB thinking it would recognise it as new hardware - no joy and I think I was a bit silly thinking it would be that simple! Any suggestions on how I can link the laptop to my desktop to retrieve the contents of the hard drive? Can I do this via USB? If so do I need some software? I can't load anything on the laptop but can to the desktop.