Really odd Torch rebooting problem

So I've got myself a Torch with Bell...and it likes to reboot every 5-10 mins on its own. It'll reboot when mobile network is on and connected to Bell. However it won't reboot if I have mobile network off or if I have the SIM removed from the device...so this is leading me to believe it's a problem with the SIM

HOWEVER

It functions perfectly fine, SIM in and connected to Bell, when it's plugged into the wall or computer. This is what's really got me baffled. I'm going to try wiping and reloading it and if that doesn't solve it, then trying out a new SIM

Anyone else have any input or problems like this with their torch?
This SIM was used perfectly fine in my unlocked 9000 since February btw..

EDIT: So I just did a software wipe and reload...no dice. Yes it is .246

EDIT #2: This thing heats up. Fast. That is when mobile network is on. Took a closer look, something is definitely funky with the sim or the sim reader. That;s the source of the overheating and more than likely why the BlackBerry crashes when no sim is inserted or when mobile network is off...although it doesn't explain why when I have it plugged in, it doesn't act up. Will update as soon as I've got my hands on a new sim card.

EDIT #3: It doesn't crash when data is turned off...hmmm...

UPDATE: So today, got a new sim card...no dice. I had got my Torch from Kijiji and I had no reciept...but I ended up calling Bell as I was out of options...the sim reader is definitely defective. Apparently the Torch was not activated before on a different account or something like that, so all in all, I can take this to get repaired...they're considering me the "original owner". So it gets to go out to Flextronics for a couple weeks. Not bad at all considering I could've been SOL. Will update when it gets back!