Didn't work for me. I followed everything step for step, all OK till I tried to set the Windows 7 partition active. It would not allow this, got an error message saying it was not possible.
So I reloaded everything back from the System Restore image you so helpfully suggested creating and I'm back where I started.
The only thing I can think of is that the drive I have my Win XP and Win 7 partitions on is not the first drive, it's Drive 3, I think. But I'm sure I was on the right partition as I used the 'Detail Partition' command, so I know it was the right one.

I'm going to have another try tonight when I get in from work, so any thoughts on where I went wrong?