Some apps are gone and others crash after Samsung Galaxy S2 crash I'm facing a problem with my Galaxy S2. I've been using it for 1 year but a week ago when I used the alarm clock to set an alarm, the phone suddenly hanged and restarted. After the restart it stopped working properly. At first all of my apps crashed even the TwLauncher. So I turned it off and then tried turning it on by removing the memory card and simcard. It didn't work out, so I used my Nokia for a week and left it with battery, simcard and external memory card removed. But this weekend I turned it on and it started working with less app crashes but some of my apps were gone like opera mobile. Also I had to re-enter my Google account because the phone was like factory reset. All data was there, the only thing gone was my Google account.

Now my problem is all my apps are crashing when I enter them and sometimes a text comes to the screen saying "Oooops !! I crashed but a report has been sent to my developer"
How can I fix this? Any ideas? I can provide screenshots if needed. Any help would be helpful.
It sounds like something has corrupted within your phone.

You didn't say if you forced a factory reset - that would be my first suggestion.

Failing that, you're left in a tricky situation.  The only think I can suggest is to root your device and install a new ROM over top, I tend to advise people to install Cyanogenmod.  Luckily there are complete instructions for doing that over at the Cyanogenmod wiki.

Good luck.