jailbroken iphone 2g wont switch on past 'pineapple' logo

a friend of mine gave me his iphone 2g to 'sort out' before he sells it to someone.

its jailbroken and the program it was using was something called 'cydia'

ive never jailbroken anything so i dont know much about it but i went to settings > erase all data option to restore the iphone...


...but now when i switch on it wont go any further than the black screen with the apple logo (although in this case its a pineapple)

any help would be appreciated.


P.S. it is not recognised in itunes