How old is the machine? The most important question is: what motherboard is in it? You're probably better off getting the motherboard manufacturer (possibly Intel) and model, and going to their web site for the manual, than trying to get it from Packard Bell or anyone on this site. I doubt 1/2 the ppl here can remember jumper settings from the last board they owned. At least I can't.
As a last resort you can pull the battery from the board and wait a minute, then re-insert. Of course if it's soldered in it'll be a bit of a project.
And you may have to throw in an ext. battery pack after that, if the machine's really old.