I have the same problem and a couple of websites have pointed out the difference between the "Windows Installation Disc" and a "System Recovery Disc" made form copying the recovery partion of the hard drive.
I'm also running an HP Pavillion, and in mine, I can access the recovery mode by pressing F11 whilst it is starting up (before you get to the error screen) but this only lets you reset the system, whereas I think the W.I.D. may allow you to just reset the Windows OS, without losing everything youi've already got.
I don't KNOW that this is the case, but it's almost certauinly worth getting your hands on a copy of the WID before you wipe the system.
MS have made available the Disc, a copy of which is hosted here:
of course you may well be in the same position I am of only having access to public computers which don't have bittorent or any disc burning facilities :(
In which case, what jay said: get hold of MS, or HP, or PC World, or maybe even your local computer geek, if you're lucky any of them ought to have a WID.