Thanks finally i resolved the problem guys thanks!

Its still doing the same thing with 5.1.1 When i don't use it for a while then i press power / home button to switch it on a white screen then it changed to yellow and stay stucked there...then i have to switch it off and on again then it become fine its annoying :/

I didn't understand you XD could you please explain me ?

okej so now i downgraded to 5.1.1 and still doing the same thing but when i try to switch it on first a white screen then a yellow one...then i have to turn it off and on and works perfect...so now i think its a hardware problem or what?

any good guide to down grade to 5.1.1 plz? it keep on doing it and its annoying me Thanks.

is there a fix for it ? im restoring it. any idea ho i downgrade to 5.1.1 with itunes?

So guys i got an iphone 3gs with iOS 6.0 its everything fine and works fine but...when press the power button and don't use it for a while and then i press the power button to use the iphone it stays black! the screen won't turn on. so i have to press the power and home button for 10 seconds...