date problem

hey, i have a problem, i was recently working inside my desktop computer running XP pro, i had the power unplugged of course, so, i went ahead and moved around some of my PCI cards, which was my intent, after i was finished, i put the case back on and plugged the computer back in, when i tried to turn it on, it wouldn't come on, so i unplugged it and put everything back the way it was before i moved stuff around and i got an error upon turning the pc back on, it said, CMOS error, please reconfigure bios by pressing F2 (in my case pressing F2 brings me to BIOS setup), so i fixed everything in the bios, but now my computer says that the date is January 1st, 1600. this is definetly not right, if anyone can help, i would greatly appricieate it. (right now my computer says it is january 8, 1600 as this happened a week ago)

 

You can change the date and time from the bios suggested >there is a date and time icon in control panel. If the date and time gives you trouble change the battery