I just got at P5Q deulxe and i installed my ram 2x2gb and 2x1gb stick and i installed windows 7 everything was working and suddenly today i coudn't stat my pc . i got blue screen and i always crashed at startup when i wrote my password.
So i decided to test my ram
and when i was testing them one by one i found out that one stick was not working.
But while i was doing this i forgot ones to unplug the PSU and the motherboard had power(light was on) and i removed and installed a ram. Now it says inte the manual that you should unplug psu becuase it can damage componet ( i think they meen ram because it was on the ram installing page), or the motherboard.
Now is there any way i can cheek if my motherboard is allright and nothing bad happend to it?
I am in windows that meens that it is working. I wan't to be sure that everything is okey.
What is the possiblity that something will get damged when someone does this kind of mistake?
Don't worry about it. You said your system is working, so it is highly unlikely that you did anything to your motherboard. Just don't make a habit of working on your system with the power ON.
Now, to the more important question of your RAM. You should try to test your RAM using Memtest86+. You should download it from here, and make sure you get Version 4.0 because it is the only version that works with 4 GB or more of RAM: http://www.memtest.org/
One more question
when i install 2x2 gb and one 1 gb stick windows 7 chrashes just like the way it did with the bad ram.
You should be able to test your memory sticks one at a time in the primary memory slot, but otherwise the RAM should be installed in pairs. If you already know that one of your memory sticks is bad, I would RMA it. Fortunately, you have a good working set of RAM, so will not experience any down time.