Hello I know i'm a new user but i arrived here so you can help me fix a problem I have with my pc. Yesterday i wanted to change my OS to windows 7 64bits (I had windows 7 32bits before and worked just fine). The installation goes well but when windows install tries to reboot to complete the installation it hangs on "windows start" and reboot again and again. I tried several solutions such as - Install using a different cd (3 different cds and same problem) - Install from USB flash (not even working) - Fix boot system (from command prompt using windows repair cd) - Re-install windows 32 bits (same problem) - boot in Safe mode (same problem it reboots again and again) - Windows system repair (from cd) But none of those solution worked so I arrived here hoping you can help me find a solution to my problem and thank you in advance. PS:I have a Dell inspiron M 560 (Core 2 Quad, 4Go in RAM).