Hi Anil
Welcome to the club!
I have EXACTLY the same problem with which I have been grappling for
about six weeks with absolutely no progress.
I have posted here three times already on this and have been surprised
at how few, if any replies I got. It really seems like there is no
sure-fire fix for this one despite it apparently being a wide-spread
problem.
Trawling through some other newsgroups pointed to re-installation
(which you have tried unsuccessfully) and re-registration of the
jscript.dll and vbscript.dll files as possible solutions.
This latter I have tried. However, while it succeeds in the Admin
account, it fails in the user account wherein exists the wmp 10 problem
and, in the end, made no difference to the availability of wmp 10 in
the stricken account.
Interestingly, I did achieve a few days temporary respite by carrying
out a repair-install of WinXP. However, the problem reappeared after a
few days.
Good luck!
Paul