Okay, so i was going to try jailbreaking my ipod touch 3G 4.2.1 But when im told to turn off my ipod touch AND KEEP IT connected i turn it off, then it turns back on. and i cant jailbreak it with it on im told.
Are you sure it is connected properly because if you detach and reattach the iPod, it will turn on. You could try another USB port and/or cable to see if the connection is just poor and thus the iPod thinks it has been reconnected.
I have the same problem or something similar.
Here are the steps
1: Ipod 2G connected to computer (note using windows)
2: Ipod switches on and charges
3: disconnect Ipod from Computer when finished charging
4: Can use it then no problem for as long as battery lasts
5: switch off Ipod using On/off switch on Ipod
Problem is I cannot switch it back on manually using On/off button.
Have to plug it back in to to computer to get it working.
Have restored it to factory settings and upgraded it to 4.2.1