Windows 7: Win 7 suddenly won't restart

I attempted to reboot today, but I can't. I'm told to go through the startup repair sequence, which appears to successfully load files, then I see a brief set of arrows suggesting something is going on, but then the screen goes blank and stays that way. Won't start normally either. I'm running Avast Internet Security on Win 7--both set to update automatically.

What should I try next?
Thanks,
Brian

Try tapping the F8 key during Boot-Up, see if you can get into Safe-Mode. Let it load completely to the desktop. Then try power down to re-start & see what happens.

F8 doesn't get to a safe mode on this machine. It starts with an ASUS bios screen all the time, even when hitting F8. I still get to the startup repair option. At that point, I've also selected 'start normally' and continued to hit F8, but don't get to safe mode that way either. It hangs on the Starting Windows screen.

Might there be another keystroke on this box to get directly to Safe Mode? I'll post to an ASUS help forum as well to see if there's a way to bypass this start screen.

HI bpreston,

If you can't get to Safe Mode using F8, then spam F5 until you get a menu asking you which OS to boot. On a single boot system you should only have one option.
Then press F8 to get to the advanced options and select Safe Mode from there.

Hope it helps

Thanks. I got into safe mode, did some of the checks there. Troubleshooting found no problems and the process suggested trying recovery. I noted the last recovery point was the automatic system update on 3/16. I ran recovery and noticed it went through the first part of the process quickly, but shutting down was very, very slow. Then it hung on restart at the starting windows screen. Makes me wonder if others have had problems since the 3/16 update.

I forced a shutdown and started once again, this time trying 'repair your computer' from the F8 screen. I did get the startup repair screen to open. It bumped along for a while, then asked me if I wanted to use system restore. I said yes again. Then another restart request, and the system would not shut down, again. I forced another shut down and started over at the repair your computer option. Ran Startup Repair from the prompt once again.

This time it ran for a longer time without suggesting a system restore. I am noticing that the dialog box suggested that the system might restart several times during the process--I am hoping this might happen...since it hasn't been able to actually shut down normally at any point so far.

Looking at the repair details, one message failed: System files integrity check and repair, faile, error code = 0x490.
Back to system restore, I scanned for affected programs from the 3/16/11 date and none were found. So I attempted another restart. It would not shut down.
Forced it again. Restarted into Safe Mode, tried to shut down from there. Got to shutdown and it wouldn't finish. Rebooted and couldn't start in safe mode this time. I went to a 3/13 restore point to try again--the 3/16 restore had not worked. It ran the restore, went through to restart, and locked up at the Starting Windows screen.

Next?

Have you tried to run System File Checker in Safe Mode ?

SFC /SCANNOW Command - System File Checker

Tried to start in safe mode with command prompt. Could not start. Trying again in vanilla safe mode.

Now when I try to start in vanilla safe mode, I get only a cursor arrow on the screen. Won't get beyond that point. Also tried last known good configuration. This time it went to the starting windows screen but didn't get beyond that point. Next?

Can you get into regular Safe Mode ?

then

Start cmd.exe then the sfc /scannow

At this point, selecting safe mode doesn't complete. I see a list of files that seem to load, but when that finished, I get a cursor arrow in the middle of the screen and nothing else happens. I can move the cursor, but it's on a black screen.