iPod Video Stuck in error messages cycles

I have an iPod Video which I only just re-discovered after it was lying around for maybe 2 years, I tried to charge it but nothing happened, so I proceeded to open it up, as soon as I got the black case off it turned on, and to this moment which i'm typing up it goes in the cycle of "please wait battery very low" to apple logo to the sad iPod face. I have tried resetting it (menu + select) dozens of times, and i've put it into diagnostics mode, it passed the auto test but got stuck on the FWPWR one, and i've even put it into disk mode but iTunes still won't detect it. Any ideas? I haven't tried reconnecting any cables YET. ALSO i tried smacking it mildly on a paper pad as other forums have suggested, but still the same state.