You're lucky that it only took PC World 2 days to fix your computer.
It took them 2 weeks to fix mine and it's a replacement model, so I lost all of my things.
The good thing is, I didn't have any really hard-to-install games on it, only Peggle, ROBLOX, Sonic Adventure DX and Sonic Riders so all was well.
I just hope this PC doesn't break or I'll be super pooped if I have to re-install all those Steam games.