Partition Problem

I had Windows Vista Ultimate and Windows XP Sp2 installed on my system. The Vista took about a 10GB partition. Later I reinstalled my Windows XP Sp2. So obviously I have one OS - Windows Xp Sp2 now. But thing is that I have lost the space occupied by Windows Vista!!! When I go to DISK MANAGEMENT from Control Panel I see a partition colored as Black saying Unallocated space!!!! When i right click on this partition the partition style is shows as MBR! Also when I try to partition it by right clicking on it there is no option of Create Logical Drive!!! The option given is of New partition! However when I proceeded using this option I lost 2 of my earlier drives!!! Later i recovered using Active partition recovery! Again I have the same problem!!! Also Partition Magic 8 is not starting up in my system! During start up it says partition drive letter cannot be identified.
What should I do now to get my 10GB space back? Can anyone help me please?

Try something different, I suggest you download the GParted boot-cd, you won't have any errors about drive letters then, and you can use it if you can't boot.

But I would suggest you back-up your valuable data before proceeding.