You may as well download the rest of the stuff HP has at that site for your particular PC.
You may not need it or even want it, but just in case, now is the time to get it rather than later.
If you do a clean install, you will get a bunch of drivers directly from the install disc and you may not need much or anything from the HP downloads.
I'd probably try the HP recovery as a last resort before a clean install---if you don't get any further assistance in this thread.
When you get that Windows 7 ISO downloaded and burned, you should confirm that you can in fact boot from it. If you can't boot from it, it's useless. If it boots, you can cancel out at the first screen, remove the disc from the DVD drive, and reboot to your current installation.
If you figured out your exact model number, you may as well add it to your system specs.