Helllo.
Y have a litle problem. Everithing what y do im my phone makes an error.. opens "menu" cause system error mesage, contacts, games, evreythin else.
y can't type character, only numbers. Applicatios do not create new icons, and reinstal assume the old subfolders.
- y already have formated and remove my MMC, used code *#, deleted the boot file in c:\ system, removed all aplications, pray, cry..
I think if this problems occuring because y can't use the text keys (only numbers), because loose a system program/module..
Anybody can help-me, y have to read all trics topics and not find nothing to do.
Sorry for don't type in your language, and my poor english.

It happened to me too and I used hard format...but you dont have 6600, so I think that firmware flash is the only solution.

No hard format needeed..
y make this:
- install fexplorer(1.13 y think, download from my page www.raptors.pop.com.br)
- at first look, y used the sistem aplications functios (y an not sure te correct name but are the last function in menu), an see what every what y need to fone make funcionaly are runing from "z",
- I find every default aplication im memory "z", all is there, in a .sis format. Cant do that, system return a message"aplication already instaled( not sure the real name, because my phone languare is Portuguese from brasil).
- Then, if y can't delete a running system  aplication, and my problem are located in "c" drive, what y do? delete boot folder(see serbian fihter tutorial form more details), after, afraid, y delete the folde whit all .ini files (yes pressed "c", inside), and sistem automaticali restore the folder whitout dump clean whith factory setings. . deleted  everything else.. sistem restart.. an they back whit no errors, can type  all chars. Icons come back,. and run more faster. Y loose all my setings (GPRS, MMS ...)(system defaults restore recomended *#)
Remember y do this only in last cases, and if "z" unit have a problem you will see the famous "white screem).
One mor time, sorry, but y don't now to talk well.
Valeu Galera, até a próxima (thanks people, until de next its all).

sorry link wrong: correct is:
www.raptors.pop.com.br/wap.htm (directo for mobile)