A1226 does not support Snow Leopard oS.

Nonsense!

Pre-Installed MacOS:X 10.4.9 (8Q1058) -- Maximum MacOS:X 10.11.x*

according to:

https://everymac.com/systems/apple/macbook_pro/specs/macbook-pro-core-2-duo-2.2-15-santa-rosa-specs.html

what sort of DVD are you using to attempt this install?

It needs to be a Ful Retail, full color Snow Leopard DVD. The DVD for a different model Mac never contain "Drivers for every appropriate model Mac".

Wouldn't be a first time someone saved old-obsoleted Macs from dead-end path of Snow Leopard or Lion:

https://duckduckgo.com/?q=MacBook+Pro+A1226+and+linux+ubuntu+non-apple+os&t=ffab&ia=web

Some versions of 'alternative operating systems' offer workable software sets and more secure web access.

While I've two older Macs that run Leopard 10.5.8; do nicely. Late 2005 Mac mini 1.5GHz G4 + MacBook1.1.

Gave away dozen/dozens I'd repaired, much older & few newer; until that idea worked out of my system.

A hobbyist may consider these projects; so long as hardware replacements are available, whole or in part.

MacTracker database and Everymac ultimate lookup are my easy choices.

And knew the unit, a '15-inch mid-late 3.1 MB/Pro 2007' still had potential.

Original OS Mac OS X 10.4.9 (8Q1058)

Later OS Mac OS X 10.4.10 (8R4049), 10.5 (9A581, 9A3129)

Maximum OS OS X 10.11.6 (15G31)

Yet, your opinion was to 'low-talk' fair outdated machine. My daily user

(2012) mac runs El Capitan 10.11.6; in one of its two internal hard drives.

Near end of the line. Even then, may be ubuntu/alternative in its future.

Well.. i agree with you in principle..... it’s not really worth doing.. especially if you have to buy more ram sticks ( memory) for it now.. max ram for this is around 6 gigs. for pete’s sake, its used value is around $200.. and it was made around 2007..

jb