Did you check for Win7 drivers on the HP site before attempting this OS upgrade ? They may not support Win7 and using Windows Update to go out and find drivers is a recipe for disaster.
I assumed my friend knew what he was doing installing Window-7 in older notebook (6yrs) with less memory.
You are right,,my driver can't support window-7. I will have another experience person installed original
Window XP. back in. Thanks for your support.