WMP12 wipes MP3 information!

I have Windows 7 Professional 64bit installed on a brand new PC.

I'm using the default WMP12 32bit and like this version however...

For about the third time WMP12 as updated the folder that I keep my extensive mp3 collection in and erased the data that you find in Details in the files Properties.

In WMP > options > library>
"Automatic media information updates for file" isnt ticked.
"Retrieve additional information from the internet" isnt ticked and this means that the following is greyed out:
*"Only add missing information"
*"Overwrite all media information"

So can someone tell me why half of my collection gets wiped???

Thanks in advance.

Thanks for the reply.

None of my mp3 files have their "read only" box ticked.
When the computer erased half of my files the ones that were left still didnt have the "read only" box ticked.

My mp3 files consist of legally purchased ones, ones ripped from my CDs and files from my converted vinyl. A mixture of these were both in the wiped and normal!!!

If I cant find a cure then its off to Winamp or Mediamonkey...

Thanks for all your advice, help and options, still no help though.

I just opened WMP12 and at the bottom of the screen just right of the volume control the legend "updating media files" popped up with moving arrows and guess what...?
My files have been wiped again.

Thanks WMP12.

I'm off to Winamp or Media Monkey.