Virtual Device Driver error after installing 8.20

[Dave_Thomson]

    After installing LV 8.20 and the associated drivers, my computer exhibited the odd symptom of reporting an error like "16 bit Windows Subsystem   An installable Virtual Device Driver failed Dll initialization.  Choose 'Close' to terminate the application." whenever I tried to run any old 16bit program.  I found some hints on the forums, and found that it was likely related to the GPIB driver installation which altered a key in the registry.  A google found a fix that advised deleting this key, then readding it, at which point its value would be blank and things should work.  In my case, that process resulted in the error box no longer showing up, but the 16bit programs still would not run.  By comparing the registry to that of a similar machine, I found that the relevant key (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\VirtualDeviceDrivers\VDD) had been altered by my antivirus program.  By giving the broken machine's key the anti-virus-related value of the VDD key, things began working again.
   Anyway, 2 points:
   1) Installing NI drivers shouldn't corrupt the registry in such a way as to prevent 16bit programs from running.
   2) The problem may be more complicated than the current DevZone articles indicate, since other programs (like my anti-virus) can also alter the relevant key.

[Adam W]

Hi David,

Thanks for reporting this.  I was wondering what version of Windows you are running, and also, if you have the link to the fix you mentioned so I can take a look as well.  That is definitely a strange situation.

Thanks again,

Adam W
National Instruments

[Dave_Thomson]

Adam,
   I am using windows XP Media Center.
   There are several items on the NI KB that refer to the GPIB driver causing this type of problem.  They helped point me in the right direction.  But to get a solution, I had to google the error.  I came up with this:  http://support.microsoft.com/kb/254914/

Regards,
    Dave