Why? HDD's are pretty generic these days. I was assuming he didn't have a RAID setup and even then, swopping a drive over is child's play. It's not as if he's going to be actually
playing the game at his friend's; simply getting to the desktop, getting online and downloading the patch is all he wants to do. As for the internet connection, he would've already setup his own PC to his friends ISP account as he did before. And why is his OS relevant? Even if he has multiple OS's on different partitions it makes no difference. The only real issue would be if his friend didn't have enough RAM to run Vista - I believe it will
run on 1GB (good enough to get to the desktop - which is all he wants), so that's pretty likely too. Most BIOS's are self-configuring and I doubt he'd even have to go into it to change anything - just swop hard drives over and boot. What exactly would cause the bluescreen you suggest?
Of course, I'm assuming he's intelligent and already knows all the ins and outs of hard drives, master, slaves, that sort of thing. All I was doing was throwing a helpful idea out there to save him some time and effort that can do no harm in trying it (besides the blindingly obvious, like dropping the drive in a puddle).
I say try it. Might actually
save time, compared to lugging all those cables and monitors around. Of course... his friend might just have a laptop...

