Resolved Windows XP W/SP3 media player issue

I have a XP Dell E521 with SP3 and the media player just stopped working, message, "Windows Media Player encountered a problem while playing the file. For additional assistance, click Web Help. Web help was no help. I use the media player each and every day. The problem just started today. I had Series 9 and down loaded 11. The files I play are AVI files, not that it matters I was able to play all files up until today.
I checked device manager and all appears to be fine. I rolled back to 9 and this is where I stand. Any assistance would be appreciated.

 

Have you tried to run virus and malware software ?

If not then run them and download version 11 again and reinstall it and see if this helps.

 

Two excellent replies, I'll run a scan and download the codec.

 

I did run a virus scan and Norton's returned no issues. Believe it or not, the WMP is now fine. I'll close the post and keep my fingers crossed. Thanks to all.