Hi, camorri, and thanks for your quick answer. No, I wasn't running Compiz, although I tried logging in with that as well.
Apparently the problem was more serious as my PC was running extremely slow or was not responding at all. Yesterday after copying a few files to my external drive only the Num Lock and Caps lock indicators on my keyboard were blinking, but the system was completely dead. After turning off my PC manually those two kept on being alight. Strange that innit?
So I decided my only option was to format and reinstall which is what I did and now am a happy person again.
I believe the culprit was the Wine emulator which I installed just before all the problems began. As I said I'm a complete newbie and could be wrong, but I would never ever again try using it and will install a proper XP alongside my Mandriva distribution. Unfortunately abandoning Windows entirely is not an option for me.
Thanks again. Wish you all good!
Regards: K