Thanks again for all the comments and advice.

I must put some minds to rest : this isn't my one and only PC, I have a desktop which is running fine, though reaching saturation point, but which was never partitioned. So when I got this laptop, nice and empty, running fast and smooth even though far from new (the E6400 is a real workhorse), I thought it might be a good idea to partition it before filling it up with all sorts of things.
However I don't have the installation CDs for it but if I had I wouldn't have hesitated in going ahead with the partitioning so that if things went wrong I could start again from scratch.

But I'm following your advice and will leave things well alone.

BTW MiniTools looks pretty good and it does offer to either Split or Resize-Shrink - thus my OP.

Thanks again.

I have just inherited a Dell E6400 laptop with a 80gb hdd, nothing much installed on the single C:/ partition, though there is some precious data there that I've backed up elsewhere.

I would like to create a second partition to store data - what is best : to split C:/ into two partitions, or re-size (i.e. reduce) C:/ so as to free unallocated space and create a new partition ?

I would be using MiniTools Partition Wizard or similar.

The whole thing is a bit nail-biting ... advice please.

Thanks.