Hi, had a date/boot problem for a long time and
What was happening is this: At first the computer refused to boot at all... pure black screen no writing, so knowing my battery was propbably flat, I would leave it on for a minute or so, reboot again, and contrary to what many IT so called specialist say...the flat battery would get just enough charge to boot past the bios, and would then get to a black screen saying blah blah blah, and to continue press F!, which would boot me to windows but with a corrupted date. From there I would change the date and continue as normal. The problem was that everyday was the same like ground hog day. I put up with this for a year and followed many advice online and changed the battery several times... but to no avail. The fix was so simple in the end I cant believe others and myself could not see it. It wasn't until I finally saw a 9 year old boy show it on utube. All that was required was to change the date in the bios to the correct date and it now works perfectly.
Just thought I would put this up for any others who had simular problems. You see, my cmos battery was flat so long that it lost even that tiny charge required to keep the time in the bios. This computer was not used as much as my other one... hence the long time flat battery. The lesson? When battery probs occure... always check Bios time.