[Solved] How to change back to IDE from AHCI?

How to get back should be easy. The system has not written any damaging data to your hard drive. It simply can't understand its data stream this way.

You need to enter the BIOS Setup screen system and make the change there. On most machines, you do this by holding down the "Del" key while it boots up. After a few lines of info in the POST sequence, it will suddenly put you into the opening screen of BIOS Setup. When you do this, watch the screen closely (it changes quickly), often near the bottom. If the "Del" key was the wrong one, you'll see a prompt about which way to enter Setup.

The Setup system is a bunch of menus where you can see and change parameters. There will be prompts on the screen, usually to the right and bottom, about what keys to use to move around, how to change some things, and what your options are. Find the menu page (probably by moving across the top level of tabs) where the SATA hard drives are configured. On that page you will see the ports and at least one, maybe all, will be Enabled. Close to that will be the port mode, usually setable individually for each port. Choices may include IDE (or PATA) Emulation, SATA, AHCI, or RAID. Set your port to IDE emulation as it was originally. Now look at the bottom for the key to Save and Exit - often F10. Confirm and the system will save your settings and reboot that way. Should work smoothly now.

Just FYI, in many places in the BIOS Setup screens there are key settings that can disable your machine and make it hard to recover. There are also lots of place, like the one you just changed, that make a difference but can be changed with no problem and then changed back again if necessary. I generally try not to change anything I don't understand. To help, read your mobo manual. Among other things, it usually will tell you how to recover from a really bad situation by resetting the BIOS to fatcory defaults that work, just so you can get back in to fix things. But you rarely need that - I've never had to. It's just there is case....

The behavior you describe does not sound like a hard drive porblem. Just to check, disconnect both the power and data cables to your HDD and try to boot the machine into BIOS Setup. I bet it will behave the same.

What this sounds like is the CPU cooling is inadequate. Typically is the CPU fan is not running, OR if the heatsink is not fastened down tightly to the CPU, this happens. The CPU stats up normally but warms up quickly inside. With no heat removal it soon gets to its upper temperature limit and shuts itself down, and that typically takes 5 to 15 seconds.

Examine your CPU cooling system. See if it seems very solidly mounted on there, or is there some wiggle or wobble to it? If there is any looseness, the heatsink is not fastened down tightly. If that does not appear to be the problem, start up the machine and watch the CPU fan. Normal operation would be for it to come on immediately to full speed, then slow down a little after a few seconds. If it does not run, fix that.

Best answer selected by xStaticX.

> I tried that Registry tweak on my system, and Win7/64 Ultimate could not find the boot drive.

Are you referring to the one I posted? I've had several people post that it worked fine for them. If it did cause you a problem, how did you recover?

Did you ever get your system switched over to AHCI mode? If so, how did you do it?

Thanks for the feedback BTW. When I describe the procedure in in the future I'll mention that at least one person had a problem with it.

I dunno if this will help, but I just read a post about this on another web site and it advised to not only set the ...\Services\Msahci "Start" value to zero, but also the ...\Services\pciide "Start" value as well. (Actually, the post said "PSIIDE" but I'm pretty sure that's a typo as there's no such key on my machine).

That's probably just required so that the procedure will work in both directions (IDE -> AHCI and AHCI -> IDE), but it might be worth trying.

Nope. Tried again. My PC won't even see the DVD drive if I make those registry changes; it can't even boot off the Windows 7 DVD. Changed it back, and had to do another repair of Windows 7.
Might be time to call the knacker for this Abit IP35 Pro...

Yes, the BIOS change prevents booting from my SATA DVD drive. On the Integrated Peripherals page is where the SATA mode is set; it can be IDE, AHCI, or RAID. It only works when set to IDE. The mobo is an Abit IP35 Pro, which has a ICH9R on it.
So yes, "changed it back" refers to the SATA mode in the BIOS.

First off, I'd really like to apologize for this thread hijack, even though it's on topic.
Second, I did some searching on this issue, and apparently the Abit IP35 Pro has some BIOS issues with this (there was even a thread at THG). I did not lose my USB keyboard during this process, but the other problems with SATA devices seem to apply. I don't have the final BIOS, just the v17. Since everything else seems to work, and v18 didn't solve this problem, I'm NOT going to flash it; my mobo is an orphan, and support will be sketchy at best. The Q9450 is too competent to toss, but I'd hate to spend money on S775. I'm not sure what I'm going to do yet.