In the past 5 nights I went to the desktop twice (while playing BF2). Then tonight my rig rebooted, upon the next restart I got nothing, blank screen. So per instructions of the intel manual I pop the CMOS battery. Upon the next reboot I get a long "siren" as they call it. We'd call it a constant beep. Intel mobo instructions say overheated CPU. I dismount cpu check paste layer, nothing abnormal. Scrape clean apply new thermal paste, reboot, now everything seems fine. Any ideas what might cause this after months of trouble free hard core gaming?