Can an iphone 3Gs which is disabled be enabled again?

Can an iphone 3Gs which is disabled be enabled again?

No, that would be illegal, if the phone has been locked/blocked/disabled then no company or person can legally unlock/enable the phone.

Through a computer, yes it can, the only reason it would get disabled is because of too many pass word failed attempts, you will have to do a full reset on the phone and it will be like new as when it was first bought, you will need iTunes installed on the computer or laptop to reset the device, once reset just go through the set up on the device, CAUTION: you will need to have any kind of sim card in the device to reset it this way, this is the same for any iPhone, iPods don't need it, good luck with your phone

Yes, but as it is no longer being supported by Apple and most current software will be useless it will really only be useful as an iPod.

Assuming you bought it disabled, the reason it is disabled is most likely because it was stolen. Turn it on again, and Apple can pinpoint who stole it--you.