I have a Dell Dimension 8400 and get a low battery message on boot up. Short of pulling the mother board to look, how do I find out what battery I need to purchase and are they available at stores like Best Buy etc?
*Edit* FYI you can buy these almost anywhere. Wal Mart, Lowes, Home Depot, most electronics stores, etc. It's a common battery used in tons of things ranging from computers to car keyless entry clickers to garage door remotes to toys, and countless other devices. And another FYI, it's located on the motherboard behind the PCI-e slot, next to the south bridge.
(Sorry to butt in here, I have just had the same issue - about to go out and find me a CR2302.)
Additional question - after changing the battery - and switching the PC on, will I have to re-set all my time, date etc? (I understand that the battery keeps the BIOS CMOS ticking even when the PC is plugged out.)
What surprised am I looking for when I switch the PC back on?
Just enter the setup option when you power it up (the exact key sequence vaires, some computers use "DEL", "F2", "F10", etc.) Most computers' defaults will get the machine booting again, but you'll need to re-set the system clock most likely.