I have a custom built computer with an Intel core 2 quad, Asus P5Q MB, 4GB mem, Seagate 500 GB drive, using Win XP Pro, SP3. It's been working fine, but suddenly this morning the dreaded window opened that starts "We apologize for the inconvenience......etc." Then lists several possible ways to start Windows, including "Start Windows Normally". However, the screen is frozen - NON of the arrow keys do anything, everything is frozen - nothing happens,

Any ideas?1) When do you see that message and what is the entire message?

2) What is new or different since the last time everything worked properly (ie, new hw, new sw, virus, error, etc)?The message appears very early - right after the screen displays the name and model of the Mobo.
The message is quite long - and I'm a slow two finger typer!! Here goes:

WE APOLOGIZE FOR THE INCONVENIENCE, BUT WINDOWS DID NOT START SUCCESSFULLY. A
RECENT HARDWARE OR SOFTWARE CHANGE MIGHT HAVE CAUSED THIS.

IF YOUR COMPUTER STOPPED RESPONDING, RESTARTED UNEXPECTEDLY, OR WAS
AUTOMATICALLY SHUT DOWN TO PROTECT YOUR FILES AND FOLDERS, CHOOSE LAST KNOWN
GOOD CONFIGURATION TO REVERT TO THE MOST RECENT SETTINGS THAT WORKED.

IF A PREVIOUS STARTUP ATTEMPT WAS INTERRUPTED DUE TO A POWER FAILURE OR BECAUSE THE POWER OR RESET BUTTON WAS PRESSED, OR YOU AREN'T SURE WHAT CAUSED THE PROBLEM, CHOOSE START WINDOWS NORMALLY.

SAFE MODE
SAFE MODE WITH NETWORKING
SAFE MODE WITH COMMAND PROMPT

LAST KNOWN GOOD CONFIGURATION (YOUR MOST RECENT SETTINGS THAT WORKED)

START WINDOWS NORMALLY

USE THE UP AND DOWN ARROW KEYS TO MOVE THE HIGHLIGHT TO YOUR CHOICE.
SECONDS UNTIL WINDOWS STARTS: 0.

Nothing is new or different since the last time everything worked properly.You say the system is frozen at that screen. It's unlikely it's frozen - more likely you are using a usb KEYBOARD and the system can't see it at boot. Are you using a usb keyboard? If so, try using a ps2 connection. If not, we'll have to talk about a repair install.No, I am using a ps2 connection.Well, then I think you are going to have to do a repair install. Boot to the XP cd and choose the SECOND repair option. XP will install on top of itself. Done properly, all settings and apps will remain intact. You'll have to go to Windows Update to download and install all updates.Thanks for all your suggestions. I tried them all, but no luck. Today I finally reluctantly took it in to the local computer repair service. They wiped the hard disk clean and re-installed Windows. Hope all is well now.
Thanks again.