S60 Phone Error: Nokia 5500, "App. Closed: Calendar" (Solved)

I've got a problem with my mobile phone, Nokia 5500 Sports, bought 3 months ago.

Phenomenon:

1. Phone detail: Nokia 5500 Sports, 3 months old. Symbian OS v9.1 (S60 3rd Edition).
   More detail from Nokia forum: http://www.forum.nokia.com/devices/5500



2. Can't open the Calendar program. Before the Calendarprogram's graphical user interface was fully displayed, it crashed, exited automatically and an error message "App. Closed: Calendar" displayed by the system



3. Entries in Calendar: two daily morning alarm entries. 3 to 5 other appointments. Very few data



4. Every morning at the time when the daily morning alarms are supposed to ring, the whole phone would HANG. No operation is possible except for the "Task Switch" (long press Menu key), which would bring up the task list but no further operation is possible. The only way to recover is to remove the battery and wait until the display faded out



5. Memory usage of phone main memory: half. Memory usage of memory card: 1/3



6. I can think of NO particular operation that may be designated as the cause. Daily use is very common: phone, SMS, camera, web surfing, notes, etc.



7. Haven't synced with PC before. After this problem occured, I tried to sync it with my PC by using bluetooth or IrDA, everything was synced successfully except the Calendar



8. Two custom themes downloaded from local operator's website



9. One or two custom rings transferred from my friend's MOTO phone by using bluetooth, 2 MONTHs AGO



10. Installed 3rd party programs: Gmail client (Java)



11. 2 weeks ago I've transferred 3 small Java games from another MOTO phone. But those games can't run on my phone & I deleted them



12. Phone software edition (by dailing *#0000#): V 03.18 07-09-06 RM-86

Fix attempt:

1. Reboot the phone, no help


2. Sync with PC, no help


3. Remove those custom programs & themes, no help


4. Reset to factory settings (by dialing *#7780#), no help


5. Whole phone backup, then format C: (by dialing *#7370#). After formating, the Calendar is OK, but after I restored my data by using Nokia's PC Suite, the Calendar broken again

Analysis:

My first guess is that the Calendar's data files are corrupted, so the bet maybe delete those files to reset the program. But for this 3rd edition of Symbian OS, I can't figure out which files are its data files (after a long search on net)! I checked some of the folders under C:\system\data but no good luck.

Solution:
Format C: (by dialing *#7370#), then sync my contacts back to phone. The trick is to avoid using whole system backup, which would keep the corrupted calendar data files.

PS:
I wanna try "Nokia Phone Software Update", but I've no cable now.