When I use WMP it freezes after 30 minutes, the sound carries on but the picture froze. The error message is:

Windows Media Player encountered an unknown error. This can occur when another program or operating system component encounters a problem but does not comminicate the nature of the problem to the player. (The report is attached)

This happened last week so I tried installing WMP 11 but this still freezes. I re-installed WMP 10, still freezes.
The video (avi) runs fine on VLC Media Player but I prefer WMP.

I have run a Norton Security and Windows Defender, both report the computer clean.

Any suggestions would be much appreciated ?

My computer info is attached

I would do another reinstall-- but AFTER you uninstall -- download and run the registry cleaner from my sig below. Uninstallers are notoriously sloppy.
I suggest running the unnecessary files search-- delete those
and then the registry search-- and delete those
Easy Cleaner's default settings are very safe-- no need to worry.

THEN download & install Windows media-- and when installing --temporarily disable your anti-virus app. They can interfere with installs.

Post back with results-- if you still have issues --we'll dig deeper.

I have tried uninstalling and run EasyCleaner (unnecessary files and registry search) as suggested.
However, before I re-installed I checked that wmp was gone. When I requested to run a video it just run on wmp and then stopped after 31 minutes (it was fine on VLC media player). This time the message stated :

ymsgr-tray-wnd:ymsgr_tray.exe - bad image

Is there something in XP (SP2) that does not allow wmp to be deleted ?

I tried restoring to a month ago, did not make any difference so I then un-restored back to now.

Any help would be much appreciated.

That ymsgr_tray.exe-- is part of Yahoo messenger -- you have yahoo toolbar installed ??
The error indicates to me that there is either a corrupted file in it -- or there's a conflict between it and VLC player...

VLC is fine, this program runs correctly (also Real player is OK).
It is wmplayer that freezes.
I removed Yahoo completely but wmplayer still freezes after 40 mins.
I get these messages
Alcwzrd: ALCWZRD.EXE bad image (this is the RealTek Audio program)
Removed wmplayer and run Easycleaner, re-installed wmplayer, still freezes after 40 mins, I get this message
DIEmWin: atiptaxx.exe bad image (this is the ATI300 program)

Again, any help much appreciated

Thanks, Jeff

Try this :
Uninstall WMP again
open regedit-- under hkey Local Machine/Software/Microsoft/Windows Media-- right-click and delete all folders. (they will be recreated @ reinstall)

Then run Ccleaner's Registry scan clean all files found

now reboot.
download/install a fresh copy of Windows Media Player