What version of 3.7 did you upgrade to?
3.7.1.37?
3.7.1.41?
3.7.1.91?
3.7.1.115?
etc.
(See Options->About on BlackBerry)

I think it's time to install a different operating system.
I bet it will fix your proboems.

This is because there are so many different versions of 3.7. SOme of them are buggy. If you want the best version of 3.7, I highly recommend Cingular's 3.7.1.115 which is newest (115 is bigger than 37 and 41):
https://www.blackberry.com/SoftwareD...ient=Rc4cZBaBN
Select the 7280 device. The 7230/7280 software is the same.

If you have always been interested in trying instant messaging (VeriChat MSN/ICQ/AIM), it is time to upgrade to BlackBerryOS 4
http://www.blackberryforums.com/viewtopic.php?t=1995