USB Mass Storage won't work

[faheemraza]

I have a blackberry 8310. My media card works fine from within the device. but when I connect it to my laptop, no drive appears in My Computer. Media card support is enabled, I've formatted the card both from within the device and from my laptop (using an external card reader).

Can someone please suggest what could possibly be wrong with my blackberry?
My other Blackberry 8320 works fine with the same laptop with all same settings.

[codered78]

Try switching the cards between the two phones to figure out if it is the card or the phone.

[faheemraza]

Same card works fine in other phone when connected to the laptop. Also it was working fine with OS version 4.2. It stopped working after the upgrade. My phone gets charged when connected to the laptop, only the mass storage isn't working.