Thanks,

I'm now pretty certain that it's a hard disk fault.

Today, the machine has been making horrible clunking noises, and I can barely get as far as windows before it dies.

Nicole,

The machine has two NICs in order to share a cable internet connection (the reason why I networked them to begin with)

I could connect the cable modem via USB. Once I've got a new hard drive sorted, do you think that'd be a better option?

Ed