ipod touch 2g MC 4.2.1 stucj in jailbreaking

[pyzon94]

i have been trying to jailbreak for days and been running into problem after problem. i have had it jailbroken it on 3.2.1 or something like that but had it stolen when i got it back it was already updated and everything. ihave tried downgrading and jailbreaking with both redsnow and greenpoisn but same problem with both. when i try entering dfu mode my ipod becomes unrecognized by computer and wont connect to computer till i restart my windows! then i would just try again but nothing is working. i also relized that when i looked closly at ipod that there was some black lines or something. nut anyway i just really want it jailbroken PLEASE HAELP!!!!!!!!!!!!!!!