Then I recommend resintalling from USB. Download the three files I told you. Place everything inside a folder and run the EXE, it will extract all the needed files to install. You can use the first program here to create the bootable USB. Remember to follow the instructions to install a non-Ultimate version if needed.
Once you get to the install process, select a custom install (not upgrade). Then you will get to the partitioning screen.
I recommend doing like in this tutorial (for Windows 7). Delete all your partitions (including any strange HP_TOOLS or recovery partition), and once you have a single "Unallocated Space" label, install Windows Vista there. (This will create an additional partition to enable a "System Repair" option on the F8 boot menu.)
If you have any doubts, ask us.