how to go back to 10.5 fron leopard

since i installed snow leopard i can't use my hp1315 all in one to scan with so i need to convert back to 10.5 how do i do that?

The only way is to do a compete reinstall of the OS. If you have your grey install dvd that came with your Mac ( presuming you have had Leopard installed on it when you got it) then shove them in and do a install like you did SL.
It also helps if you post your Machine Specs as well so we don't presume anything
If you haven't got the disks anymore you can ring  and maybe just maybe they will have some spare disks somewhere or you go on ebay and pay a premium price for them $100+ is what you will be looking at.
Are you sure there are no drivers for your HP ?? I would take a look but om out the door to work.
Good luck and I'm sure someone else will chime in where i left off

Cheers

Before you reinstall, I suggest you read this. Person got it working!

Snow Leopard os 10.6 - Page 2 - HP Support Forum

Might give vuescan a try first. Free to try.
EDIT: I meant before re installing the OS. Didn't see Dennis' potential solution until I had posted.

VueScan Scanner Software for Windows 7, Mac OS X Lion, Linux, iPhone, iPad, iPod

i tried doing this and it didn't work, one question when he says printer powered at logical places when are those logical places?
thank you