Windows 7: startup problem after power outage

Any help would be appreciated! I'm out of ideas...

Dell Inspiron 546
Windows 7 Professional 64 bit

Had a power outage while computer was running. When I restart, it hangs at the “starting windows” screen.
Startup repair usually hangs at “windows is loading files” but occasionally works, so I've been able to try a few things from the windows recovery environment.
I have a steady amber light on the motherboard.

Here is what I've tried:

1) Ran Windows startup repair. It says it cannot repair the system, and gives this error report:

Problem Signature 1: 6.1.7600.16385
Problem Signature 2: 6.1.7600.16385
Problem Signature 3: unknown
Problem Signature 4: 21200262
Problem Signature 5: Auto Failover
Problem Signature 6: 3
Problem Signature 7: BadDriver
OS Version: 6.1.7600.2.0.0.256.1
LocalID: 1033

2) Ran Windows memory diagnostic tool. Completed successfully, no problems found.

3) System restore. Restored successfully, but did not solve problem.

4) Boot from factory Windows DVD (known good disc). Hangs at “windows is loading files.”

5) Boot from Dell “Drivers and Utilities” disk. It boots successfully, and I have two options: memory diagnostic, and system diagnostic.
Memory diagnostic runs and reports all tests passed.
System diagnostic hangs at “Initializing USBEHCI.MDM”, so it never gets to the menu where you can run the actual test.

6) Ran Bootrec.exe from command prompt.
Tried /Fixmbr and /Rebuildbcd. Both completed successfully but did not solve problem.
/Rebuildbcd reported number of windows installations found = 0
I haven't tried /Fixboot, because lately I haven't been able to get the recovery environment to load.

7) Removed all extra peripherals, no change.



8) Removed RAM one at a time and tried restarting, no change.

9) Removed hard drive and plugged into another machine. Was able to access it and recover all my data with no problems.

Unplug all USB connections and power cord. Press and Hold power button for 1 minute to drain power. Then plug back in power cord, try powering up.

If this fails, can it boot into Safe Mode?

Try resetting BIOS to defaults: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS

This should enable DVD to boot correctly. If not try tapping the one-time BIOS Boot Menu key at boot to trigger DVD.

Work through these steps for Troubleshooting Windows 7 Failure to Boot starting with HD diagnostics and Disk Check.

Held power button for 1 minute while unplugged, tried booting again, no change.

Cleared CMOS, reset BIOS to default settings, saved, powered off, tried booting again, no change.

Status right now is:

- Boot normally > hangs at "starting windows"
- Boot into Safe Mode > hangs at system32\DRIVERS\CLASSPNP.SYS
- Boot from Windows DVD > hangs at "starting windows"
- Run Startup Repair > hangs at "windows is loading files"

I'm also getting a single BIOS beep when I power on, which according to the Dell manual is a BIOS ROM checksum failure. Not sure what to do about that other than clear CMOS? Hopefully it's not a symptom of toasted motherboard.


I'm going to put my hard drive into the other machine again and see if I can manually replace CLASSPNP.SYS from my install CD.

Looked through the steps in your link, all but one of them require something I can't get to right now. The only one I'm able to try is burning a partition wizard CD and see if I can boot from that - I'll try that next.

Did you reflash the BIOS recently? Look at the BIOS version in BIOS setup or on flash screen to see if it is current against the latest download on Dell's Support Downloads webpage.

Is there a way to flash or reflash the BIOS from boot? You may need to ask Dell.

Unplug the HD to see if disk will boot. Try Windows 7 DVD or Repair CD, or a disk which is known-good. Sometimes bad boot sector code will block BIOS post requiring wiping the HD in another machine to reinstall.

Tried unplugging the HD and booting from the windows CD - same as before, hangs at "starting windows."

I've never flashed the BIOS. Looks like I'm a couple versions behind.

My service contract is expired, so Dell won't talk to me unless I pay by the minute. I don't want to do that, because I imagine it will involve paying them to go through some unhelpful script before getting to my actual question.

However, I did find this - instructions for making a bootable BIOS update CD for Dell machines. Think I should try it? Anything else you can think of to try first?
Update Your BIOS Using Bootable CD

Boot your HD maker's HD Diagnostic extended CD scan which should autostart on its own to test the HD. Afterwards if it finds nothing then do the quick wipe, which should in turn force the installer to autostart to reinstall. Clean Reinstall - Factory OEM Windows 7

When you get into Windows 7 I would do the BIOS updates right away to get a confirmed working version.

If you need to rescue files first use Paragon rescue disk to recover data which also autostarts on its own.

If this fails you may be forced to flash your BIOS but I would study it further and wait for more help from those who have done this.

Ran HD manufacturer's diagnostic, no problems found.

I'm not clear on how wiping the drive would enable me to reinstall, since I can't boot from the windows DVD even with the HD unplugged? Does having an empty HD versus no HD change the behavior of the boot CD?

Yes, when a disk cannot be booted by the user then you can force it to boot itself (autostart) by wiping the HD with Quick Wipe function on diagnostics CD, DBAN, Partition Wizard disks which also autostart.

You saw the HD diagnostic disk autostart. That is what should happen.

Okay. I have to quit for the day, but I'll try that tomorrow.

That worked! Here's what I did exactly:

- Swapped out the HD for a small spare I keep around for backups
- Booted from the HD manufacturer's CD and used it to wipe the spare HD
- Booted from the Windows DVD, install ran successfully
- Rebooted into my new Windows install
- Reflashed the BIOS per Dell instructions
- Swapped back to my original HD

After that, I am back up and running as normal. Didn't even have to reinstall any software! That's a big time savings since this is a work computer with lots of specialty software and complex settings.

Thanks Gregrocker!

Incidentally, there is a roaming IT consultant my [very small] company uses when I can't solve something - I asked him about this, and he said it wouldn't work. Glad I tried anyway! You're a rockstar.