If you want to try to repair Vista follow these same steps for Troubleshooting Windows 7 Failure to Boot
If you're ready to install Windows 7 wipe the HD first using Diskpart Clean Command
from the installer's Command Line accessed by DISKPART At PC Startup.
Try triggering the installer to boot by tapping the HP ESC key at boot. This is almost always a failure by the user to boot the installer or Repair CD correctly.
Failure to boot a disk is 90% of the time user error, reset the CMOS: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS
. Set HD to boot first in BIOS setup, use ESC key to boot installer or boot disks.
If this continues to fail, download and burn to DVD or write to flash stick the latest official Installer with the tool provided in Clean Reinstall - Factory OEM Windows 7
to see if the installer is the problem.
If not then download, burn to CD using Windows Image Burner then boot free Partition Wizard
bootable CD or DBAN CD which will boot itself without user prompting, wipe the HD from Disk Tab after highlighting the HD #.
This will force the installer to also boot itself so you can follow the steps in Clean Reinstall to get a perfect Windows 7 install.