Hi, Hopefully it will stay set, but>
As posted already, it's usually the motherboard battery that causes this problem with time/date and other odd things like settings not "sticking" when you restart/start up....
Could be the BIOS itself but that is rare. I can't say that a new BIOS flash now would even help, there is a chance you may mess up and result in a non usable machine. I've done quite a few BIOS updates and not had one problem, but you never know, and I know you will get some replies about not attempting a BIOS update, perhaps a few with agreement to try an update...
If it were my computer, I would get another battery and try that...
Usually they are long lasting, and right out of the package fine to use but again, you never know.
When you install the new battery, are all unplugged> put the new battery in etc, do you have to
then set the time and date, and any other special settings manually in the BIOS screens? Usually you do have to as the settings revert to the original system date /BIOS date....
There may be a jumper on the mobo that you have to move, to CLEAR CMOS.... (it may have the letters CLR next to the pins, usually you'll see pin 1 2 and 3, 1+2 are Normal (regular startup position) and pins 2+3 jumpered for just a couple seconds, with the battery out, clears the data from the CMOS back to factory settings and you go from there and change what you need to, set Default settings or any special settings needed, you may have a motherboard manual to help with this....did you set this board up when you got it?
For some motherboards, just taking the battery out won't clear the CMOS you also have to have the jumper physically moved over one pin as above, then put it back, and then put back the battery, etc....
Follow the mobo manual>>> best idea here!
How Windows keeps track of the date and time
Anyone install any extra date/clock apps? There are some freeware things, that are used to workaround expire-ware programs, that try to fool the program so you can use it for a long period of time...I'm not saying you did this, just mentioning it> they usually would not set the date back 2 years, though....
Did anyone try time synchronizing tools, that may override the system clock?
Here are some things to look through for ideas.
http://labmice.techtarget.com/windows2000/timesynch.htm
I've heard of machines just losing time, but not like yours, with the year two digits off....