BB Curve :: Unlock Key Locked / Frozen

my Blackberry Curve 8900 is completly locked. The screen is only on when I put the phone in the charger, but my problem is also that the unlock key at the top is locked, so even when there are lights and energy in the phone I can't unlock it, and therefore I can't use it at all. I've tried pulling the battery out and in again about 3 times. I've tried taking both the battery and the sim card out. I've tried connecting my phone to the computer, which it can, but it didn't help me since the phone is still locked. I've tried resetting it by pressing ALT + CAP + Del. but that doesn't work either.