First, your profile says BlackBerry 9300 but your carrier is listed as Sprint. Something isn't right there as the 9300 is a GSM model but Sprint is a CDMA carrier. The exact version matters for software updates.
It sounds like the battery is shot. When connected to your pc it's charging via the USB port.
Sprint stores will let you try a new battery before you buy. Most have extras lying around for this sort of thing. After sorting out your battery issue (if it is indeed a battery issue) you should wipe the BlackBerry with JL_Commander and re-install the handheld OS onto your device. How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ How do I upgrade the OS on my BlackBerry? - BlackBerryFAQ
You can find the latest version of the OS for your model in a sticky at the top of the 9300 discussion. Choose wisely.