Dynamics hard disk unreadable? But its a new drive? HELP?

Can anyone help i have just changed back from Vista ultimate and had a 250gb hard drive which is newish and has got over 2000 music albums on it and i know it works fine.
However i have now changed to XP media centre and i have plugged the drive into an sata port and it is showing UNREADABLE and it is now a dynamic drive and if i convert it to basic it says i will lose all data. How can i stop this from happening or will have to ghost it to my other 250gb drive which fresh format but will it then say DYNAMIC unreadable!

Someone Help me please! cant afford to lose all this great music GOD WHY THEY DIDNT THEY JUST LEAVE IDE ALONE!!