Windows 7 - Won't sleep; system restore doesn't work

I noticed about a week ago that my system won't go to sleep unless I force it to sleep using the using the Function and F1 buttons on the keyboard. I also noticed about the same time that I tried to set it to use the ribbon screen saver and that doesn't work either. The screen saver looks fine in preview but it won't start up on it's own.

I tried working through the "Vista sleep problems" tutorial that was posted in a previous thread but none of that helped. I also tried doing a system restore several times and each time I get a window telling me that "system restore did not complete successfully becasue system restore couldn't access a file, probably due to anti-virus software. An unspecified error occured during system restore 0x80070005." I've tried disabling Norton Anti Virus and running system restore -- same result.

The rest of my system seems to be running fine and I really don't want to get into advanced recovery methods or doing a full restore of Windows if I don't have to. I don't know if this would matter but I did install a second internal HDD. It's not in any kind of RAID configuration or anything. I use it to capture/store video footage and I keep backup copies of several personal folders on it. I think sleep was working for a time after I installed the second drive.

Any advice to get sleep to function again? Thanks.

Thanks.

Try running SFC, might be a corrupt dll.

What's SFC?

Thanks.

System File Checker. Check this tutorial SFC /SCANNOW Command - System File Checker
If this doesn't work...
Deal with that later.

Turn off the screensaver and see if it sleeps.

If not, update the video driver.

Use free Revo uninstaller in Moderate mode to remove the Norton bloatware, then install the expert's choice free Microsoft Security Essentials for a lightweight, nearly invisible solution with no noticeable system impact. Turn on System Restore and apportion as much HD space as possible.

Next, click through the WEI score at Computer>Properties to choose Advanced Sys Tools, then choose Performance log to see what is happening at the moment it tries to sleep.

What is the suspend setting in BIOS - S1, S2 or S3?