Question : Invalid drive specification from dos disk.  No drive found error/status code:0120

XP now fails to boot.  Was running for months, then got NTLDR error.  Now get "invalid drive specification" and "no drive found error/status code:0120" from dos floppy in a: drive.
Hard drive and Floppy drive both show up in CMOS
Floppy, CDROM, HDD-0 Boot sequence in CMOS

Please advise [had tried about 20 different things].

Thanks,
Joe

Answer : Invalid drive specification from dos disk.  No drive found error/status code:0120

If the diagnostics don't work, I suggest that you download Darik's Boot and Nuke.
http://dban.sourceforge.net/
Create a dban boot floppy or CD, boot from it and wipe your HDD before trying again. This usually takes several hours.

But before doing that it would be worth trying to fix your MBR. I wouldn't be too hopeful though.

Boot from your XP CD and run the following commands from the Recovery Console:

fixboot
writes a new startup sector on the system partition.

bootcfg /default
restores boot.ini

fixmbr
repairs the startup partition's master boot code.

If you're not familiar with the Recovery Console, here's how to do it.

To start the computer from the Windows XP CD-ROM, you may need to configure your BIOS to start from your CD-ROM drive.

If you don't have a CD or can't boot it you need the floppy disc set - download and setup instructions from here:
http://support.microsoft.com/kb/310994

To run the Recovery Console from the Windows XP CD or the Windows XP startup floppy discs:

1.  Insert the Windows XP startup disc into the floppy disc drive, or insert the Windows XP CD-ROM into the CD-ROM drive, and then restart the computer.
Tap any key or click to select any options that are required to start the computer from the CD-ROM drive if you are prompted.

2.  When the "Welcome to Setup" screen appears, press R to start the Recovery Console.

3.  If you have a dual-boot or multi-boot computer, select the installation that you must access from the Recovery Console.

4.  When you are prompted, type the Administrator password. If the administrator password is blank, press Enter.

5.  At the command prompt, type the appropriate commands to diagnose and repair your Windows XP installation.

For a list of the commands that are available in Recovery Console, type recovery console commands or help at the command prompt, and then press Enter. Or check the link below.

For information about a specific command, type help commandname at the command prompt, and then press Enter.

6. To exit the Recovery Console and restart the computer, type exit at the command prompt, and then press Enter.

More information here:
http://support.microsoft.com/kb/307654#3