Hi,
1. Is this issue confined only when playing WMV files?
2. Have you made any changes to the computer prior to this issue?
Follow the methods mentioned below and check.
Method 1:
Refer to the section “What can I do about video problems, such as green or pink lines appearing in the video, flickering or choppy video, the Player stops responding when playing video, and so on?” from the link mentioned below.
http://windows.microsoft.com/en-US/windows-vista/Play-an-audio-or-video-file-frequently-asked-questions
Method 2:
Try to re-register the file and check.
a) Click on Start.
b) In search window, type cmd and press Enter. Right click on cmd and choose Run as administrator.
c) In the command prompt window type regsvr32 wmvdecod.dll and press
Enter.
Method 3:
Follow the steps mentioned below.
a. Open Screen Resolution by clicking on the Start button, clicking on Control Panel, and then, under
Appearance and Personalization, select Adjust screen resolution.
b. Click on Advanced settings and select
Troubleshoot, and then click on Change settings.
c. Move the Hardware acceleration slider towards none to reduce or turn off video hardware acceleration.
d. Click OK, and then restart the computer.
Also refer:
The screen may appear black or green during playback when the Windows Media Player control is embedded in a Web page
http://support.microsoft.com/kb/909554
(this article also applies to Windows Vista)
