I am writing this as i am restoring my 16 GB Iphone 3GS for the 3rd time in less than 2 months. I noticed this problem after i updated my 3GS to iOS 5, and hoped that this problem would be resolved with iOS 5.0.1 update. However it is still persisting. The problem is basically that the iphone will reboot/restart by itself periodically. I've noticed it always reboots/restarts when its "Searching" for a signal but it also does it even when it's not "Searching" although with far less frequency. The first few times it restarted i thought it was a bug when i updated so i restored it. I've noticed that once i restore, the problem seems to go away but after a few days it comes back, after further time the frequency of the restarts increases until eventually after 3 weeks it becomes totally unusable restarting every 2 mins. I'm restoring it for the 3rd time right now, but this is really becoming annoying, and i was wondering if there is any fix to this? I've noticed that other people are also having this same trouble. Any help would greatly be appreciated. Please note iPhone is 2.5 years old so no warranty.