Windows 7 - Windows Media Center - Refreshing the cache?

I am trying to like Media Center but I've got some issues that are testing my resolve!

1) It reports double the number of tracks for some albums. When I goto an album to view the track listing every track is listed twice.

2) If I go to an artist it lists the albums ... but some of those albums do not appear in the main album section.

3) Under artists it insists that I have got "Guns N Roses" and "Guns N' Roses" (note the single quote). The ID3 tags are perfect and clearly state "Guns N Roses" so where is it getting the rogue spelling from? I suspect that it is a reminant of when it was downloading duff info from the net

4) If I go to artists, select "Guns N Roses" and then select "Greatest Hits" it tells me there are 28 tracks. Actually there are 14. It then goes on to list the tracks ... except it lists hundreds of tracks. It is listing every track from EVERY album I've got titled "Greatest Hits" regardless of artist.

As far as I am aware "Another one bites the dust" was not a hit for Guns N Roses

When I added my mp3 folder to the Music library last night I left MC overnight so it could finish its indexing.

I have turned off the "download info from internet" but I suspect this info is still stuck in a cache somewhere.

How can I delete the index and start from scratch?

ps Guns N Roses is just an example. Please don't flame me if you don't like them

UPDATE : I've removed all folders from the Music library but it is still happily showing music entries?

I think I've solved most of my issues.

I've removed and then added my folders to the Music library this has solved the double entry problem.

I've also just discovered that Media Center uses the "Album Artist" tag. I always considered this an optional tag and ignored it. I concentrated on ensuring all my artist tags were perfect.

It appears Media Center uses the album artist tag and not surprisingly my Guns N Roses albums contained "Guns N' Roses" and "Guns N Roses" as album artists.

UPDATE : Correctly populating the "Album Artist" using MP3Tag sorted out these issues

It also appears that all my "Greatest Hits" titled albums had no album artist set so MC considered all by the same artist ... ie the artist with no name.

So if I spend the time correctly populating this tag most of my issues will disappear