cyrnel

Do you see an "Import Foreign Disks" option? If so, try it.

If not...
Did you use any partitioning tools other than Disk Management?
Did the disk boot on a box with an older version of windows?
Either of those could have damaged the volume(s) which would mean some reconstruction or recovery is required.

Disks set up as "Dynamic" require more effort to move between systems. They use a database stored with the system to map what should be to what's on the disks. While this is helpful for multi-disk filesystems it can cause issues when moving between boxes. Avoid dynamic unless you know specific reasons why you need it. Never use it for a disk that might touch WinXP Home or earlier win versions.

Edit: I wouldn't worry about a hardware failure at this point. XP obviously recognizes the disk is present, it's dynamic, but it doesn't know how to interpret the contents. Now it's time to import if possible or learn more and repair if possible. If we can't get it to behave then it's time to attempt file recovery.