You can't get the key now that you installed W7 - that wiped out the original key. Plus, the original key before you installed W7 was most likely the manufacturer's key and not the one you were assigned and that is on the label. You need to try harder to read the label - otherwise you will not be able to activate the product if using a Vista Installation Disk.
Also, the Recovery Disk you are downloading will not contain the option to restore to factory conditions using the Recovery Partition - it simply isn't included on that disk (but the disk is still a good thing to have even if it can't be used in this situation). But it may still be possible to do this using the
other article Imperfect1 provided and going to the Advanced Recovery Options article
http://www.vistax64.com/tutorials/88009-advanced-boot-options.html and using F8 to see if the option exists there. If so, you're in luck and just choose that option and you'll be able to restore. It is also
possible that restoring this way may use the manufacturer's key and you may not need your product key to activate - but I'm not entirely certain about that. The best I can suggest is to try and see if it activates. If so, you're home free. If not, you will need that original, unique Product Key and the only way to get it at this point is from that label. The manufacturer will not be able to help and Microsoft can't help - neither record that information so that it can be recovered and tied to your machine.
If that doesn't work for any reason, try the options I recommended. The recovery partition option may do the trick (and may also not require the product key - but again, I'm not certain but it's worth a try). If you need to get recovery disks from HP, first confirm they can be used without a Product Key otherwise they will be useless - they will install but you won't be able to activate. The Vista Installation disk option most definitely requires a Product Key.
If you find you need and can't get a Product Key, then your only real choice is to repurchase the operating system with a fresh new product key (if you can find Vista for sale anymore) or purchase a full install Windows 7 installation disk (assuming you don't already have one and not just an upgrade disk which will not work without first installing and activating Vista) and do a clean install and start from there (I assume it works on your system so there's no need to verify it is compatible).
I hope this helps.
Good luck!
