Is it this one?
http://h10025.www1.hp.com/ewfrf/wc/manualCategory?cc=us&dlc=en&lc=en&product=3867474&
This looks like a "PC in a box" model. Not made for customizing, locked down to reduce service calls.
It's probably not there. It shouldn't be needed as I've found SSD's to work fine without that change. There may be a few performance hounds that think it will make it run faster but we know those types.
Bob
as it says,i upgraded my old comp with a new samsung 840 evo SSD,i cant find in my bios where to change the settings to AHCI...my comp is a presario sr5710y and the mobo is MCP61PM-HM (Iris)...rather frustrating... only thing i came close was sata/pata settings but all it allows is to enable or disable........anyone have any ideas?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic