Vista "sleep" problems on my Asus p5K mobo HTPC

If your Power LED is flashing, I don't think you're in Vista's "Sleep" mode.  With our Vista installs, when you hit the power button on the Remote (which defaults to Sleep mode) the computer appears that it's off entirely (it's not) and thePower LED goes dark until you wake it - WinXP's "Standby" mode caused the LED to blink when we were using MCE 2005. 

Generally speaking you need to set "S3 Only" in the BIOS before you install the OS.  With my hardware, I really didn't need to do anything else.  On some MB's, in order for the USB IR transceiver to work properly you need to be sure jumpers are set for power to the USB ports in standby - mine don't - but I've had them both ways.

You can also check your power settings and make sure your power down settings are right and choose which mode is active.  (there are some different choices in Vista)  Again, for me the defaults are correct, the only thing I change is probably "allow hybrid sleep" - I turn that off...

I'm experiencing the very same thing with my new Vista build. When I originally built it and configured it, S3 worked perfectly in every respect. Now, I can put it to sleep but it wakes sometimes later (could be 90 minutes -- could be 9 hours) and then won't go back to sleep. It does wake for scheduled recordings, but then won't go back to sleep then either. The only major difference between when S3 was working properly and now is that I configured networking (ahhh...networking! ). I'm still trying to figure out what the dealy-o is.

As I've disabled most services that I would imagine would wake the system, I'm pretty sure the system is waking to refresh the network connection. This theory is backed up by entries in the system log.

I have WakeOnLAN disabled at both the BIOS level and the driver level. I also have the "Allow this device to wake the system" option unchecked for the ethernet driver. Doesn't seem to make much of a difference, though.

Come to think of it, this issue only arose after I updated Vista with all the neat-o patches you get to do after a new install. Because I initially had a problem installing my networking controller, I wasn't able to update Vista for a week or so after I built it. That was when the system was working great in regard to S3. Maybe SP1 for Vista will right the wrongs introduced since the initial code release ().

Try right clicking on the MY COMPUTER icon and choosing MANAGE from the context menu (I think that still works).  I am currently at work and I don't use Vista here, I will verify when I get home and post, If someone else hasn't already answered.

Yes, finding what you want, after moving to Vista from XP, is a bit of a challenge.  Some things are cool and others are "Why did they have to change that?" 

Have you double checked the ADVANCED hardware settings of your NIC as well?

The system logs should be in the same place as XP. Just like Ugadata said, right click My Computer>Manage>System Tools>Event Viewer>[logs].

@Ugadata: Yeah, I've turned off any of the NIC advanced properties that I would imagine correlate to some kind of wake-up capability (but I'm just shooting in the dark at this point).

Hmm. Well it's still not network related in my case I think. I've managed to get it to sleep on its own again. All I did was restore all the default power settings, change from S1 to S3 in the bios, then went back in and customized the power settings. Oddly enough, it's working again. I just don't get it considering I hadn't changed anything in between when it had been working before and now. I have to assume a program I installed is what caused it. Something was changed somewhere that I just couldn't find.

Oh, and the LED does turn off for S3, but not S1 for me.

By default, "auto" had been set in my BIOS. I forced it to S3 myself. Then I went into Vista and reset the default power settings there as well.

By the way, just wanted to remind you that I have the P5K SE so there might be small differences beyond just the layout of the boards.