I copied this link from a reply to another query similar to yours.
http://www.zachd.com/pss/pss.html#medialibrary
Dr Zach knows what he is talking about, but the answers do rather assume
that technologically, you and I know what the heck he's talking about, too.
I remember using this last time my son inadvertantly downloaded wm10,
leaving me with the same problem you describe. On that occasion I was able to
bin the hated wm10 and re-install wm9 which has never yet failed me. Now,
however, the mighty MS corp has seen fit to stop us doing that. When you read
the fixit, it jumps you to the previous line where you have to find and
rename your media library. I have XP and all I did was to copy the filename
including the %userprofiles% bit which renames itself to YOUR username
automatically, NB you will have to re write 'microsoft' in the file name, as
it is spelt wrongly in the copy. Then I opened 'search'. copied the filename
directly, re-spelt microsoft as above, and it instantly found the library. I
then right-clicked it in the search box to rename it, added the letter a to
the end of the _219 bit of the filename and that's it. I opened up the media
player and did the usual add to library by adding a folder, and it leapt into
action immediately. In case you can't find the page the link sends you to,
this is the corrected filename you need.
"%USERPROFILE%\Local Settings\Application Data\Microsoft\Media
Player\CurrentDatabase_219.wmdb
Good luck.
--
Wurze


"Tom" wrote:

> I can't open my media library and also not even import new songs... Can
> somebody help me? i don't know what to do.. maybe just reinstal it ? or
> download a extension pack ( or something like that...)?