Well for starters, your clock in the BIOS isn't set to the right time. This is probably due to a clearing and reset of the BIOS or a reflash. Or it may be the 3.3v flat battery on the board is bad.If you right click on my computer, hit properties, the system properties window will open. Go to the advanced tab, then the settings button under system startup and recovery. Under system failure you will see the automatic restart box checked. What's happening is something isn't shutting down properly when you shut down. The system sees that as an error, and does what it's been told to do. Restart. If you uncheck the box it will give you a BSOD which may have more specific info on what is causing the problem. More than likely resetting or reflashing the CMOS will fix that. Remember when you clear the CMOS chip everything in the BIOS has to be reset.checksum error points to an improper setting in the BIOS. Try discommecting the PSU power supply, and the 20 pin connector from the mobo before clearing the CMOS...