The battery's not needed. Carefully cut it out. Do your best to reseat all socketed chips. Wiggle them in their sockets, mash on them a bit or remove them and put them back in. If you not experieced with removing chips then don't do it. It's too easy to bend a pin when you put them back in, then you have a whole new problem to find. Pull the daughter card out, clean the contacts with an eraser. Then use one of those 10cent cardboard nail filers to run back an forth gently a couple of times in the slot the daughter card sits in before replacing it. Does it have a CPU card? If so, reset that too. (maybe yours only has the soldered-on CPU). If you still get no life out of the system, then it's likely one of the two 8520 cia chips could be bad. One runs the floppy, the other handles other IO and bus task. If you say the floppy is clicking, then that one is probably still good. Try swapping them in the sockets. If the second is bad, then swapping them may allow the 3000 boot but then the floppy will be dead and not click. If they both are good, then the floppy should keep clicking even after you swap them. If the floppy dies when you swap them, then you just need to find some one with a spare 8250. I've found CIA from the 500/2000/3000 very interchangable, but the 1200 and 4000 use a differnt surface mount type. I've repaired 500/2000/1200 and 3000's by replacing bad 8520's so it's a fairly common failure. Hopefully reseating all the chips and cards will do the trick. If reseats don't help and both CIA's click the floppy, then you have a very deep problem indeed that would need more help from a serious repair tech.
Plaz