|Also that message coughs up if the intended installation source files are older than the current installation in terms of service pack; at least that has been my experience recently...|
Presumably the version of the i386 etc. (and not the least its sp) on the drive is pre your current service pack - if any sp was included in that folder anyway?
Each sp does change a few rather critical files - although I'm not all familiar with just which... Thus if the intended source versions (for an installation) are older than the latest already present (installed via an sp) then you get that message...
If you were able to match vintages - at least ensure the sp on the source files is same as current version installed - you would probably get an option to repair current version. As I say above that was my experience recently...
The most you might have been able to achieve (in effect echoing wanderer's comment) re' not being able to wipe the current partition (if attempting to do so from within that OS when it's booted up) is to effect a parallel installation - if the (current) version present and the source files were similar vintage. This would give you another version alongside the existing one (giving you a dual-boot; after-which you could delete the original installation)?
If you were to contact hp you may be able to either buy (for a small fee) or download a recovery CD set? Have you been in touch with them? You can trawl hp's website\support areas to this end.
And also, as suggested by aegis1 above, it is sometimes already on the drive in "hidden" area... Have you checkd both the manual(s) if any that came with the system; and/or on-line at hp re' your model etc.?