Cause of MBR failures?

[DieHardware]

Client's PC has an 8.4GB Fujitsu IDE HDD with a bad MBR(it had two FAT32 partitions on it). I hooked it up to my test PC and AV(up to date) didn't find anything. I put it back in the client's PC, ran the Fujitsu diagnostic, it didn't find a problem with the drive. I then ran a surface scan with Scandisk, no bad clusters found.

The PC is not hooked up to the net, and only had WinME and Office 2kpro on it. The trouble started after the client loaded a "point of sale" application yesterday(received directly from the manufacturer).

What could wipe the MBR? The "point of sale" software? Bad cable? Bad HDD with an intermittent problem? Anything else?

 

[LiLithTecH]

A virus can also wipe it out.

What error are you getting that leads you to
believe the MBR is bad?

Did you try the command FDISK /MBR to clear the MBR?

Also, you can try the following:

Boot with a Windows Me Startup disk (available at www.bootdisk.com)
choose Minimum Boot
At the command prompt, type edit c:\windows\system.ini, and then press [Enter]
Edit the shell= line so that it reads: shell=progman.exe

Press Alt+F, S to Save
Press Alt+F, X to exit the editor

Reboot.

When your computer restarts, Program Manager will start.
On the File menu, click Run, type msconfig, [Enter]
Click the Launch System Restore button (on the General tab) to begin restoring your computer
to a earlier state.