date time changes randomly when restarting on battery

If I unplug the power cord on my laptop before I shut it down, then when I turn it back on the system date time is set to a random date (e.g., 1655).

This is the only thing that works (but it's a pain in the ...):
1. shut down laptop (while plugged in)
2. remove the battery (while still plugged in)
3. unplug power cord
(then when I want to turn it back on)
4. plug in power cord first
5. reattach battery
6. restart computer

(Either that or leave the power cord connected all the time, but that defeats the whole purpose of being portable!)

I bought a new battery. That didn't help. I replaced the CMOS battery. That didn't help either.

This is really annoying. Please help.

Dell XPS M1330
Windows 7 Home Premium

After you replaced the CMOS battery you'll need to go into the BIOS and reset the time there.

Your computer manual should tell you how to get into the BIOS, but it'll typically be press the F10 key on start up.

Thanks seavixen32. Actually, I already did that. I reset the date and time in the BIOS immediately after installing the new CMOS battery and it booted up with the correct time.

However, when I unplugged the power cable, turned the computer off and on again, it picked up another random date.

In that case you might want to carry out a full virus scan in Safe Mode.

Validate your OS - www.microsoft.com/genuine/validate