iPhone 3GS white screen after changing lcd and Windows 7 disable mobile service

Hi All,
I need serious help. My problem started when i bought a used iPhone with a cracked case. I bought a case online, changed it, then realized that the power button no longer works. Then, i tried to jailbreak it, and realized halfway through that i can't jailbreak without the power button. The phone then got stuck in recovery mode. Then, a friend helped me restore the old software back on it, but then his dad sat on my phone and cracked the lcd. Finally, he bought me a new lcd, and i changed it, but the phone is stuck on the white screen. i tried to restore the software from a windows xp pc, and it worked, but it still has the white screen. I can slide where the slider is and i can get phone calls on it, but still a white screen. I tried cleaning out the contacts areas for the connectors, but still no good.

I am thinking of trying to restore an older software in dfu mode to see if that helps, but i don't know how. i have been able to seemingly successfuly use DFU.exe to put it in dfu mode. Now what?

Also, my windows 7 pc turns off the Apple mobile service everytime i plugin my iPhone. Whats up with that? i cant restart it, i tried many times.

PLEASE HELP!

 

problem solved

i didn't want to believe it, but the lcd was broken, and there was a software on the pc that was messing up iTunes. i don't remember what program though. thanks for your advice.