Changed HAL Driver From ACPI To Standard PC"causing Non Boot

I changed the above setting in my device manager hoping to fix an annoying stutter problem caused with media player when my wireless signal would go out of range. I remembered changing the irq settings in win2k to solve conflicts on that system, but found that the options is not available in xp. A quick web search lead to a site which reproduced a knowledge base article from microsoft. Only, the article was truncated in a way such that the dangers of said action were not published. The drive boots up to the XP OS screen, hangs, blue screens, the end.
With my problem drive set up as a slave, is there a way to change the settings back, or manually cut and paste Hkeys, or system folders or the like to restore the drive to it's previous state? Seems logical same computer with the same installation of xp pro sp2