XP updated to SP2 vs SP2-slipstreamed: Differences?

Hello all,

I have a theory that I am trying to investigate, and thought, "who else would I ask but the guys at MSFN?".

My theory is that the slipstreamed version of XP-SP2 has some sort of setting(s) or hotfix(s)/update(s) or registry setting that are different from having an XP installation updated to SP-2 via Windows Update.

Here is the issue:

Hundreds of people (including my friend) who previously played Half-Life2 (Steam/Valve Software) on their pc with no problem are now having Direct-X issues. Some use XP-Pro, some use XP-Home. I'm not sure if any of them (except my friend) have made any changes (manualy or automaticly) to their systems.

They are suddenly getting the "Failed to Lock Vertex Buffer" error, and the game won't start. Everyone keeps passing the blame to someone else for why the error occurs.

People have assumed it was a video card problem or memory problem, but I actually discovered that it is actually a Direct-X code option to lock a portion of memory for reserved use, but it needs to be unlocked each time you write to it, and when the code is completed (the program is closed).

I recently installed a slipstreamed XP-SP2 on my friends Royalty OEM Gateway pc, shipped with XP Home (he had a messed up pc and wanted to start out fresh) then this problem started. Everything else worked flawlessly. I googled for the "Failed to Lock Vertex Buffer" message and found many pages of people who had the same issue with Half Life 2, as well as others playing completely unrelated games.

I finaly just re-formatted the PC, installed XP (non SP), then upgraded via Windows Update. No "Failed to Lock Vertex Buffer" error now. Works perfectly.

Half-Life 2 uses Direct-X 9 exclusively, and many people had to download it to use it. Some purchased the game long before others, so there is a posibility of different flavors of DX-9. In both instances, I used the latest DX-9 download from Microsoft, so I don't thing the DX-9 flavor is an issue.

My problem is I don't like not knowing WHY a non-service pack install of XP fixed it, or why hundreds of others have the same issue. It would be nice to find a fix for this problem once and for all.

Thanks