My computer is not recognising my ipod and t

hi there.. i have a 30gig colour ipod (not sure which gen that is) and i have recently upgraded to windows 7. i've tried synching my ipod for the first time since changing to windows 7 and everytime i plug my ipod in its telling me to format disk. i press format and then it tell me it cannot format the disk at this time. there is no option for me to synch my ipod, when before i was on windows vista it wouls start synching automatically when i plugged it in.. please help me!