new HTPC build, won't stay in sleep for more than a few seconds

Have run into a problem here that google has been unable to solve. No matter what, when I put my system into sleep it will resume within 5-10 seconds back into ready state. I've looked in the event viewer, and the only action taking place after going into the sleep state is a 'kernel-general' system time change. It updates the system time by a couple of seconds. The next item in the event log is the system has resumed from sleep. wake source is listed as "unknown"

I did some googling and found that some people fixed it by disabling the asus acpi. I have an asrock mobo (H67M) and this was nowhere to be found on my system. There are a few options listed under acpi in the bios (suspend to ram, check ready bit, ps/2 keyboard power on, pci devices power on, ring in power on, rtc alarm power on). Disabling all or different combinations of each did not help.

any suggestions to try here? It's driving me nuts. I'd rather not leave the PC on all the time, but it will be the only option to prevent missed recordings.

I can certainly give more detailed info on my system, but i'm not sure any of that matters at this point. Seems to be the time sync.

I seem to have fixed this, so I'll update just in case someone comes across this in a search. I found that the only devices able to wake from sleep on my computer were the keyboard, mouse, and network adapter. My fix was to go into the device manager, and adjust the power management for my LAN to only wake from sleep via a magic packet. Seems to have done the trick as the computer is now going to sleep properly and staying there until I wake it.

now, we'll see if I run into the lost tuner issue with the hauppage 2650...

hopefully it works for you. I googled several solutions that didn't pan out for me. The key for me though was finding out exactly which devices were able to wake from sleep, and then just systematically disabling and checking to see when the issue resolved.