Problem solved.
Thank you anyway
I've 2 partitions on my hard drive. I've formatted both, and installed Win7. It has crashed once and then i've re-burned my DVD and tried on the other partition (formatting again the previous one). Now, i've Win7 working but when the PC is starting, a black screen appears asking me to choose between:
Windows7
Windows7
The first is automatically choosen after 10seconds. The other does not boot the pc and the pc starts again. Why does this 2 options appear? How can i erase this second one, that i don't know how and why is there if i didn't installed anything on the other partition...
Thank you very much.

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