I also tried the specific drivers provided on CD and viewing application: Although I have not found any abnormality, I note that the driver is 2009 while that is built into Windows 2013 ... Likewise the viewing application is very old. I preferred to uninstall and return to what native in Windows 8.1 in fact I have repeatedly found that non-specific drivers for Windows 8.1 could ask sneaky PC problems whose origin was difficult to locate. Although the application provided there are some additional features, personally I do not need.
A by that the microscope image is of course satisfactory quality for the price you can not ask for professional equipment.
This product is often sold twice on other sites.
Ps: I have verified that the drivers on the CD are identical to those on the site.
Edit of 02/24/15
Following my review, the seller (Plugable technologies) offered me to test their new being developed visualization software (Digital Viewer.exe). It should be delivered to term with the microscope or downloadable from their website: Very good impression, lightweight and simple to use even if there is ergonomic few things to improve (translations in French perfectible ..). By cons regarding the driver for Windows 8.1 does not change anything I have what I have written above (native driver for Windows 8.1 preferred).