Windows XP users have been frustrated by problems which force a complete operating system reinstall if system boards are changed.

To date, the only solution to a 'Data Invalid' error when swapping out system boards has been a complete reinstall of XP, much to the chagrin of users.

The problem appears to be with the Hardware Abstraction Layer (Hal) of the XP operating system, which is a set of drivers on which the Windows NT kernel is based.

If the installed Hal is incorrect, which may be the case after changing system boards, users may experience problems ranging from certain settings not working to Windows not booting.

The problem has kicked off much discussion among XP users, and a posting today on the Annoyances.org forum suggested one workaround: "Boot off of the Windows XP or Windows 2000 CD. There is an option for a 'Repair' or 'Install', select 'Install'.

"Then there will be a 'Where to Install' option. Select the drive with the operating system already on it and continue. It will find the installed operating system and give you a second opportunity to select 'Repair'. This second option will reset the Hal."

But The Inquirer also reported a registry hack today which claims to fix the problem. In Regedit, browse to 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ENUM\PCI' and find keys with 'VEN_xxxx', where xxxx are strings like '1102&DEV_0004&SUBSYS_00011103&REV_04'.

These folders will contain a 'DeviceDesc' key which should match the hardware you are trying to install. Right click on the 'VEN_xxxx' for that device, select 'Permissions' and then check the box for a 'Allow Full Control'. This should solve the problem.

The Annoyances.org forum thread can be found here, and Microsoft's take on the problem can be found here.