XP Pro SP3 hangs at startup after upgrade from Home SP3

[scotausborn]

I recently performed an upgrade from XP Home SP3 to Pro SP3. Now the computer will not boot normally. On the startup splash screen, the blue meter stops moving almost immediately and all drive activity stops. However, I am able to boot into safe mode with network support.

Here is what I've done so far:

1. Repaired the installation with the XP Pro CD... same result
2. Ran MSCONFIG and selected diagnositic mode... will not boot
3. Performed clean boot with all services and startup programs disabled... same result.
4. Enabled the /BOOTLOG option in boot.ini... does not create the bootlog.txt file.
5. Opened System Restore, but no restore points were found even though it was enabled.
6. CHKSDK returns no problems with the hard drive.

Any ideas on what could cause this? My assumption is that the computer is still attempting to access an old system file from the previous Home version. I'm trying to avoid the nuclear option here; any advice is appreciated.

Thanks,
Scot

[EINSTEIN_007]

Why dont you try to format and install the new OS?

[scotausborn]

That was the nuclear option I was hoping to avoid.

Turned out to be the nvidia graphics driver that was causing it to hang. I uninstalled it from safe mode, booted normally, & reinstalled the same driver. No problems now, but weird that the driver both works and doesn't.