On a relatively old Windows 7 machine, it gets stuck on a blank blue screen after the Windows welcome message. I can see the mouse pointer, but that's all. Crtl+alt+del brings up the task manager, but that's blank, too. There's no way of shutting it down properly or moving forward.
I can start the machine in Safe Mode, and that seems to work, but I have absolutely no idea what to do then, apart from closing the machine down and starting it up again, which results in the blue scree again.
Once in Safe Mode, go to Start > All Programs > Accessories > System Tools > System Restore to try to find a recent restore point to take the registry back to.
If that doesn't work, have you got either a Windows 7 installation disk or a Windows recovery disk?
Thanks both. I'll give the system restore a go - don't know why I didn't think of that, although I haven't installed anything new lately. Unfortunately, we don't have the disk for Windows 7, as it was loaded onto the computer when it was bought. No recovery disk, either. Aaargh!