I need big help on this one and i would aprechiate if someone answers me this cause it bothers me for a while: my rig amd 6400+ be cooled with nitrogon no2 (stock speed) 4 * 1 Gb Geil ultra plus 800 mhz CL3 (4Gb) Mbo Abit Fatal1ty an9 32x Club 3D Geforce 8800 GTX PS Chieftec turbo 750 W HDD Seagate SATA 120 Gb all packed in Thermatake Armor full tower one day i decided to lap my cpu and heatsink to achieve better cooling. Just to add i never intended to overclock it, just wanted everithing cooler. i took my cpu off the board and lapped it and the heatsink too. when i put everything back together and turned on the computer it said CMOS checksum error - defaults loaded press F1 to continue or DEL to enter BIOS, I pressed F1 and wen't in windows everithing worked nice, i stressed tested every component in everest ultimate and nTune and all was fine, but when i restarted the computer did not respond at all, nothing just black screen with no signal. so i took the cmos battery out and replaced with new one from another computer i have and restarted, the same thing happened only this time i hit DEL and checked everything in BIOS and all was fine so i save and exited and windows couldn't load but just in safe mode so i checked everything in device manager and nothing was wrong except there was one unknown device but that's got nothing to do with this. so i restarted from this point again and the comp didn't respond again, just screen with no signal and all the fans and leds working but no keyboard or mouse active no HDD activity. so this time i took the CMOS battery completely out and left the MBO without it, then turned the comp back on and POST apeared again with the message "CMOS checksum error - defaults loaded press F1..." so i pressed F1 and it went in to windows normally (no safe mode). so i figured that's the only way i can use the computer, because if i press DEL and go into BIOS afterwards there will be no POST screen - nothing, and if i leave the battery in the MBO to save the setting same thing happens. So every time i turn off the computer the CMOS restarts cause there is no battery and when i turn it on then i have to press F1 and it loads in Windows normally, and that's how i have to use my computer now. I haven't flashed my BIOS or did anything extra besides what i said. So please if someone could help me solve this problem i would be gratefull. sorry for my english..