Help Dialing problem

[StiH]

In the last few weeks I've been experiencing weird dialing problems. If I enter the number that's not in my phonebook and want to dial it, the number just deletes itself and I'm back to the keypad. Same if I get an SMS from a new number or an SMS from my operator that I missed a call (that's another problem too lately) and I select the number that called me and want to dial it, I can't. I have to make a new contact and then I can dial the number. I checked all possible settings, thought there was a sort of security feature enabling me to only dial the numbers from my phonebook, but there's no such feature and all other settings seem normal (no blacklists, no blocking of incomming calls or anything like that). It's a pain in the a** since lately people try to call me and my phone either doesn't ring at all and on the other side people hear rings and it seems to them that I'm not picking up the phone, or I get a brief, very short ring and it's like the call is cancelled and people diverted to my voicemail. I've been installing some apps for my kid (like Talking Tom and similar lately) and bunch of others and I really don't know if this behaviour started after I installed a new app or updated an existing one, or if it's entirely app unrelated, but I'd really like to fix this (I'm backing up the stuff on the phone right now and will likely reset it to factory defaults tomorrow or during the weekend, but I'd still like to know if anyone else experienced similar problems). I even tried a 3rd party dialer from the Market (can't remember it's name), but the effects were the same so it's not a problem of the dialer on the phone, but must be a system "setting" or a bug. Any help appreciated.