Thanks for all these great suggestions everyone. Not sure when I'll get a chance to put it all in action, but I will as much as I can when I get a chance and I'll certainly post the results.

FYI, I'm 'borrowing' the laptop from my inlaw so it's definitely not a dedicated PC, nor can it be used as such. She has no computer knowledge at all (I just taught her ctrl+c the other day and she was scared at the 'complexity' of the process....) so I can certainly make plenty of tweaks to it without it causing much bother. But as for a dedicated, I think not..

I'm so used to having my PC just work these days that I forget about all the virus stuff etc (it's got the dreaded mcafee in there somewhere doing something, though not a full-on virus program I don't think).

Will let you know results when I get round to it!

Cheers

Are you recording at 24bit, 44.1 KHz? 

Dave, I was doing 24/48. That's my standard. I'm going to switch to 24/44.1 for this for now.

I'll be doing another recording tonight. I have made all the above suggested changes and will see how it goes!

I did notice that in power options, the HDs were set to turn off after 15 minutes. I hit problems at about 15:30 and around 17mins a second time. Now if I was still moving the mouse a little after hitting record, and THEN the 15 min countdown started.... This could just be it!

Will report back later. Fingers crossed!