This is my first post here, don't know if this is the right place to post this problem here.
My HP laptop was running fine with Windows Vista. I tried to install Windows 7. During installation when screen says "restarting", it never restarted even after 15 minutes. I powered off thinking I would start the installation afresh. When I powered on, my laptop didn't go beyond the HP Invent screen. Powered off and on a few times but still the same problem.
1. I am stuck on HP Invent Screen
2. BIOS doesn't show any HDD
3. Since BIOS doesn't show any HDD, Windows refuses to install and I am kind of stuck.
I once had kind of similar problem. I had then booted from Linux based Parted Magic and HDD showed in Parted Magic. I formatted the HDD from there. After that HDD showed in BIOS and I was able to install Windows successfully.
Try that out - Good luck!!