take the back cover off and check how tight your screws are.
frustrated with my lack of signal and after buying a brand new sim i started tinkering with the phone.
you might recall i got my 9000 for like twenty bucks; i was getting ready to smash it, again, and just cave in and grab a store bought one.
i tried downgrading and upgrading to different o.s's to no avail. it wasnt the tower strength either as all my friends have fully functioning 3G and network wherever we go.
i noticed when i squeezed the bottom of the phone the signal strength would increase gradually until it became a full 5 bars.
im missing the two bottom screws and one side screw thus causing the circuit board to disconnect from the front of the casing a bit. when i would squeeze the phone and travel, no more going into sos and full 3G reception everywhere.
so in conclusion, get yourself a t5 screw driver to tighten your screws and some replacement screws if your missing any as they are vital to the operation and functionality of your device.
screwdriver and screw set. for cheap! 10 Screw+T5 Screwdriver Repair for Blackberry 9000 Bold on eBay.ca (item 320517392734 end time 14-May-10 15:29:29 EDT)