Welcome to the forum.
Please see the ANNOUNCEMENT on the main forum page for the explanation of what has happened - you have been bitten by a Windows Update, that has ruined playback of WMV files.
Here is a copy of the Announcement at the top of this forum in case you missed it.
Announcement: Windows Update Causes Display to Be Blacked Out
MicroSoft has issued an Update for Windows, that is causing problems with Displays. The following is from Talbot McInnis, who tracked down this problem, and offers a fix:
"MS bulliten MS13-057. Specifically, on XP kb2834904 and on windows 7 kb2803821 is causing a problem
For us, it occurs when decoding WMV9 files. Not all uses of WMV decoding are affected, but I confirmed that when connecting the WMV decode DLL to a sample grabber for RGB32 video, the frames arrive black on top, so that points directly to decoding internals of the WMV Decode dll.
You can uninstall these windows updates to resolve your problem."
There are several threads on the problem that this Update is causing on the PrE and PrPro Forums, so one can get more details. So far, there is not another fix from either MS, or Adobe.
Also, see this Adobe KB Article: http://helpx.adobe.com/premiere-pro/kb/wmv-files-corrupted-import-or.h tml
by Bill Hunt (Jul 12, 2013)
Many, many threads on the subject. Helpful hints among them include:
For now set up your Windows Updates so that they require your notification and approval before any downloading and installing of them.
If you catch the offending Windows Update kb in Windows Updates Important Updates, right click it and select "Hide". That is supposed to keep it gone.
Please let us know if that worked for you.
Todd Kopriva, product director for Adobe After Effects just posted an update on the MS Update. Unfortunately is states that MS is working on a fix, and getting closer to that, but does not state and estimated date of delivery - good news, but still lacking a bit.
Thanks for the information. In the mean time I converted the file to another format (mp4) and it worked.
The Windows Update kb deletion should keep you from having to do the .wmv to mp4 extra step.
If you are having any problems with the Windows Update kb deletion and keeping it deleted, please let us know.
I am using a computer that has updates managed by the IT department so for now the conversion workaround will have to do.
I do not envy those Windows users, who have to rely on an IT department. Usually, that works just fine, until something like this happens.
This is why I have every program set to manually update, with just a warning to me that one is ready. Then, I can create a System Restore Point, in case things go very wrong.