Didnt know where to put this one. Every few days or so I get a file that mesures 0 bytes and is named funny like yyyyy or i or funny symbols appear on C drive. Happened on my old system too. Is this a virus of some sort? One is named 00ccc>>>>>>WWW etc...
hmm... you could try Ctrl+Alt+Del and see if there's anything weird running in your task manager maybe?
You got any sort of always-on net connection (ADSL/Cable), and if so, have you got a firewall - especially if you use file sharing software (iMesh/Kazaa), as that's supposedly full of nasty spyware and stuff. (although apparently Kazaa Lite is fine)
Beyond all that, I dunno... maybe they're left over temporary files from something like Word auto-saving documents while you type?