First you need to edit the boot file so that Vista is the only option, you can download VistaBootPRO_3.3.0 to make it easier.
You can't format XP partition because Vista has system files on it, but you can delete the files on that partition. Make sure you have all your data files backed up to the Vista partition, then select all files on XP partition and delete all. Vista will not allow you to delete any files that it needs.
Or you could move your data files & folders from XP to a new folder created on XP partition and select all except the new folder to delete.
I had Windows XP Media Center Installed and I then Installed Vista alongside it so that I could slowly migrate to it. I am now fully up and running in Vista and XP is just taking up valuable disk space. The Problem is I cant seem to format the partition that XP is on, because it is an "Active and Primary" Partion. I have enclosed a screenshot of the disk management console. So is there a way of removing XP and leaving Vista running all okay?
http://img54.imageshack.us/img54/1051/diskjy6.jpg
System Specs:
AMD Athlon 64 Mobile (S754)3200+
DFI LANPARTY UT NF3 250GB
Western Digital SATA 80GB
Nvidia 7600GS 512MBAGP
Dual Boot XP Media Center Edition and Windows Vista Ultimate

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