Vista OS Issues

First, while Vista has problems and some compatibility issues
(particularly hardware drivers), most software will work with it.
That isn't to say that every XP program works under Vista, but most
people will find that their everyday software works just fine. So
"not compatible with ANY..." is likely not going to be the case. What
software do you have that won't run under Vista?

That said, if you're having trouble with Vista, dropping "down" to XP
should be an option. Some manufacturers will fight you if you ask for
XP (especially if you've already received the machine) or charge you
extra.

If you run into a dead-end with HP, you might want to look to see if
there is a small ("mom and pop") computer shop in your area, or even a
college or university. For a reasonable amount of money, you might
find a local shop or a college student that'll find a copy (make sure
it's legal!) of XP and even install it for you. They might also be
able to help you get your software to run under Vista, if that's a
route you're still willing to take.

When you purchased the software did you know you were going to buy a
new computer? If so, did you read the specs on the software to see if
it was going to be compatable with your new computer?

When I bought my new HP computer I already knew my old printer (Win98)
wasn't going to work, so I called Brother and they walked me through
downloading the drivers for the next model up from mine, since my
printers model wasn't made anymore. Maybe if you contact the man for
the software you bought they can help you.

Also, did you open the software up already? If you did you may be out
of luck with returning it for your money back or different software
due to copyright laws on opened software. If you did, just try to be
nice and don't blow up on them. Office Max refunded every cent of the
Windows XP software I bought and tried to install.

I'm not positive, but I think you need to negotiate this with HP.
Micorsoft provides the Vista to XP downgrade media to the system
builder (Until July 2009), and then they provide it to you.

I'm not sure you can do this after purchase, but it is worth a try.
Did you ask HP?