You have a desktop Hewlett Packard computer. It had Microsoft Windows Vista installed, you went to download Windows 7 to upgrade, and it totally crashed that computer. You have gone through all steps to try to get this thing working, including getting a fix it disc from Compuserve, it won't even go into safe mode, etc.
Keeps telling you there are no Windows files and you have done everything you can think of. You have tried boot discs, F8, F5, F10, R, recovery of all kinds, back up discs that don't work, which tells you it is a NTFS system. A disc drive works, a hard drive seems fine to you, except you can't find Windows files.
You could try a chkdsk /f /r. Also, it sounds like perhaps your system configuration is corrupt. I would run a chkdsk /p or chkdsk /f if you haven't done so already.
Did you download Microsoft's anytime download upgrade to Windows 7? Did you try to upgrade to Windows 7 with a disc or a download? Not being condescending but make sure you have a DVD drive to read that disc if it is a Windows 7 DVD disc.
Make sure your BIOS is set to boot off your DVD drive or that you choose that DVD drive from a system menu to boot from. Make sure your Windows 7 disc is in drive and select that device. Hopefully, it will try to continue that installation.
I recommend installing a new copy of Windows 7 if you don't need any data at all off that hard drive.