Problems with dbghelp.dll

Hi, i recently tried to install Unreal Tournament 3 Demo and it did not work, so I uninstalled it. I remember i was trying to install some ATI drivers and .net framework 3.0. I rebooted and my graphics display was messed up. I had to roll back my ati drivers. I am thinking my problem has something to do with installing UT3 DEMO.

I've been getting this error message when i try to install windows media player 11.

wmplayer.exe - Entry Point Not Found
The procedure entry point StackWalk could not be located in the dynamic link library dbghelp.dll.

and this when i try to play gears of war:

wargame-g4wlive.exe - Entry Point Not Found
The procedure entry point SymGetSymFromAddr64 could not be located in the dynamic link library dbghelp.dll.

I couldn't do a system restore, unfortunately. I've tried replacing my dbghelp.dll with the ones on the web, but they do not work. I even did the sfc.exe /scannow with no luck.

I will try to do the windows xp repair when i get the cd(its at home).

I've tried looking for ansewrs on google, but NO ONE has this problem! :4-dontkno

Thanks!