For awhile now I had been experiencing a Checksum error on my laptop. Thinking it was most likely the CMOS battery problem I replaced the battery. When I booted the laptop I received the Checksum error and entered the BIOS setup. I changed the date and time to be correct, saved the settings on exit and the computer booted to windows A-OK. To test the new battery I did the following:
1. Restart computer with power supply plugged in - Re-booted to windows properly
2. Restart computer with power supply unplugged and running on battery - Re-booted to windows properly
3. Shutdown and then re-started computer with power supply plugged in - Re-booted to windows properly
4. Shutdown and then re-started computer with power supply unplugged and running on battery - Received Checksum error and had to enter BIOS setup to change date and time to current.
Can anyone explain to me what could be causing the Checksum error only when the computer is Shutdown and then re-started without the power supply being plugged in? Just FYI this is happening on a fresh install of Win 7 Ultimate with no other software installed. Thanks in advance for any help or advice you may have!