Monitors Randomly going blank
 

Several months ago I purchased about a dozen HP 22" monitors. My HP Laptops already have an HP Monitor connected via DVI to the Docking Station. I first purchased the IOGear DVI USB to connect the new monitors as a 3rd monitor. For most of the machines it worked fine. A few would randomly stop working. The screen would just go black. However, it was technically connected in that my mouse would move on to this screen but I was unable to see anything and it appeared as on in the display link sysem tray icon. I decided to try the Startech USB2DVI Pro device and this actually worked on those machines and I replaced the other ones that had a problem with the IOGear.

Recently some machines started having the issue with the Startech as well. It is quite frustrating. The problem doesn't stay. It comes and goes randomly.
I updated the Video drivers on the laptop. As well I uninstalled the Display link using the Clean batch utility from Display Link and reinstalled the newest Display Link Driver. Still have the issue randomly. I tried calling IOGear as well as Startech and they have no solution. They told me they sell thousands of devices without any issues.

A little about my environment.

The laptops are HP elitebook pro 6930 and 8540 (some of each of these). OS is Windows XP with SP3 and all updates using WSUS. In a Windows 2008 Domain environment. Users are locked down. (non-adminisatrtors of local machines).

Any ideas would be greatly appreciated.