[fredjacksonsan]

A new battery might work. An old one sometimes will not hold, or will not accept a charge.

I'd suggest an Advance Auto Parts (or other ap store) that offers free testing. If you can get it running with the new battery it might be a good idea to get to one of these places, tell them you are having charging problems and ask them to check your alternator output. It should be steady at (I think, don't quote me) 14 Volts, but they should have the specifications and be able to look it up.