Windows Media player uninstall problems Help!!!

OK,

I've searched the web and I've read a couple of the threads in here about WMP 10 and haven't been able to correct any of the problems I'm having. I've had problems for a while....MP would open up for some clips I try to watch with a link to download a plug (that apparently doesn't exist) but play other windows media files. Or I would be prompted to download Windows Media Player. When I tried I kept getting a message that it was already installed. I tried to remove it the only way I knew how....with the add/remove list after clicking "show updates"
I then tried to install it again. Same already installed message. I checked and couldn't find that it was anywhere. Some pages have stated that it can NOT be totally removed from the OS. I tried to install older versions but was told that they were either incompatible or that a newer version was already installed. So believing that it might still be there somewhere despite not being listed in my program files I tried to play a movie trailer clip in the windows media file format. Well, no windows player ever appeared...just an open dialog box with an ASXfile (default) option listed. I don't know what that is and I still can't install any windows media player.
I'm no techie...but I'm not completely computer illiterate either.
I'm running A new Sony Viao laptop FE550 with XP.
Can anyone help? Is this fixable??
Thanks