Hi
Dynamic disks are mostly used for RAID in servers.
Windows versions supporting dynamic disks are:
Windows 2000
Windows XP Professional
Windows Server 2003
Windows Vista Enterprise
Windows Vista Ultimate
Basic disks are supported by all Windows versions.
Basic Storage Versus Dynamic Storage in Windows XP
You cannot convert a dynamic disk to basic without formatting -
i.e. copy data on the disk to another drive, then format configured as basic.
How to use Disk Management to configure basic disks in Windows XP.