The usual battery is a metal cased CR2032 and if that took a bounce around live circuits the result is most often a dead motherboard.
The good news is that any parts such as keyboard, LCD, charger will fetch some money on Ebay.
I found an old Inspiron 1501 at work everyone said was broken so I took it home to goof around with. The unit would not power up all the way. Found the problem to be the CMOS battery was dead. However, while replacing the battery the plastic holding the battery was a bit brittle and I broke part of it. I ended up taping the battery in place with Scotch tape. The computer sprung to life. It did have some software issues so I was about to reinstall XP. While the unit was powered up the CMOS battery popped out of place before I was able to do anything and the machine went dead. Took keyboard off... replaced battery... now no power what so ever. I tried holding down the power button while battery was removed and AC unplugged to see if it would reset... Nothing. Took unit apart to see battery broke anything when it was moving around inside... nothing observable. Any ideas?