Because its a lot of text, I will ask first my question and then explain what the base problem is. Perhaps someone can give me a solution to the base problem:

Is there is a way to temporary disable mirror video drivers (through registry or so), without uninstalling the corresponding software. I tested changing the enumeration in

LocalMachine\Hardware\DeviceMap\Video

but after reboot always the old configuration is restored.

Explanation of the base problem

We are working on a wpf-project for a department of a big company. There we have the problem that WPF renders only in software mode, although the hardware they have, must support hardware rendering (Tier 2).

After searching for a solution to the problem, we found out that direct 3d does not work properly and we think thats why WPF can only use SW-rendering.

In dxdiag.exe the direct3d-acceleration is enabled, but if we start the test-routine it always fails saying that it has not enough memory (it says memory, not video memory!). I have seen there 3 different types of pc’s (they have some hundreds of each type) and every type shows the exactly same behavior. We tried to update all the drivers, also dx (Version 9.0c) and we searched a lot in the web but could not find a solution.

All the pcs have Intel Dual-Core processors or better, one type has an Intel gma 9000 graphics card the other two types have actual ATI and NVidia graphic-cards with 256MB onboard memory. Also the system memory is at least 2GB. Windows is XPSP3. The pc’s are of two different manufacturers.

Because we see the exactly same behavior on every computer of this three very different computer-types, we don’t think that this is a driver or a direct x problem.

What we’ve found in other newsgroups is, that direct x could be disturbed through mirror-video drivers such as NetMeeting, VNC and other remote desktop-installations.

In the registry, we see under LocalMachine\Hardware\DeviceMap\Video a lot of such mirror-entries and we find also the definitions in the CurrentControlSet\Control\Video-Section (However this drivers are not shown in the hardware panel of the os).

We can have admin-rights to one of these computers to test if disabling these drivers would help, but we must not change the configuration so that some software does not work after the tests. Therefore I cannot uninstall any software because I have not the mediums, licenses or knowhow to reinstall those apps. The support of this company however will only begin to work, if I can tell them what the real problem is. Thats why we search for a way to disable these mirror-drivers (or a hint to solve the dx problem if we are on a false trace)