Problem with iPhonePC Apple Mobile Device Service crashing

Hello everyone, I have a big problem. My iphone was working fine, but one day, i opened iTunes, and iTunes could not find my iPhone. I searched a lot, and i found out that, the service Apple Mobile Device crashes when i connect my iPhone. I click start, and it starts IF i dont have my iPhone Plugged. Then i plug it and it crashes. If i have plugged it and i click start, it says the service could not start. What can i do?
I tried these:
1) Reinstall iTunes
2) Reinstall Apple Mobile Device Service
Nothing works.
P.S: If i put my iPhone in DFU mode, my iTunes detects it, and it says it found an iphone in recovery mode. Then i quited from DFU, but then again my iTunes could not detect my iPhone.
Thanks for your time.
Multirama Windows 7 Nothing