Unlikely. What seems infinitely more probable to me, is you're suffering from the first stages of HDD failure, and the recovery partition on the drive was the first to go. That caused it to suddenly pop up in Windows Explorer, where it's normally hidden.
It could also be something as simple as malware.
Plenty of things seem considerably more plausible than your friend having hacked into your system. If he did, and he left something that obvious as evidence of his actions, then the guy is far from "very IT knowledgeable".
Do have to say though, it doesn't really bode well for the foundation of your friendship that you immediately jump to the conclusion that he has violated your system. If you even have the suspicion he may do something like that, is this really someone with whom you wish to be staying? This is all regardless of whether or not he actually DID anything at all.
I have a mini PC with XP and one hard drive Local disk "C". I am visiting abroad and have been able to connect to the internet wireless through a friends router. I know he is very IT knowledgeable, and we have been using our computers at the same time at several different occasions (in separate rooms) during the last couple of days. Suddenly I found a local disk named "Q" on my computer, and it doesn?t seem to contain anything. However, when I click on it to check properties I get a message saying " Q:\ is not accessible. Access is denied.
Is it possible that my friend could have remotely accessed my computer (hacked me) and thus left the trace of the new (for me) unknown local disk Q?
I would really appreciate any help in this matter!