I tried to install google map on my 8310 but failed. It says I have some java errors. And I also uninstall some unused software (I don't remember what now). And then I realized my blackberry doesn't have the phone and email icon any more. It keep saying "uncaught error: java blabla". What should I do? I used my landline to call my bb and there is no ringing tone at all but I saw there is a missed call.

Try removing the battery and reinserting it to reboot the BB.

I tried that, but doesn't work.

Is it a lot of work to reinstall the system and re-configure everything. Maybe I should just ask the IT guy to reinstall the system.

You may also want to check if "Do not disturb" is set to "Yes" in the active profile you are using. This is unlikely but still a check in case...

You might try restarting it with the SIM card out. If it restarts normally and all your icons are back, then reinsert the SIM card and give it another try. Oddly this fixed some wonky behavior with my Bold. Worth a shot before reinstalling.