Forcing me to restore? :/

Hello. My boyfriend got me an iPod Touch two days ago. I know very little about iPods, so he helped me downgrade it from OS 3.1.3 to 3.1.2 to jailbreak. The problem is that every time I close my iPod (hold the on/off button and slide to close), my iPod Touch is stuck at the screen with the USB cable pointing to the iTune the next time I open it. I plug it into my computer, opens iTunes, and iTunes is forcing me to restore. The problem is when it restores, it reverts back to 3.1.3 and my boyfriend has to help me downgrade it again to jailbreak. I really don't want to bother my boyfriend with this problem again. Any suggestions? Am I turning it off wrong or something?

Thanks in advance.

 

Thanks for the reply, tadad1. I'll give it a try.

 

Follow-up

Turns out I have a defective product. I took my iPod to the Apple Store. Even when it's restored to its factory condition and not jailbroken, it encounters the same problem. They gave me a replacement. It's been almost a month & my new iPod hasn't frozed once.