It would be useful to know the "before" condition of your PC -
What OS, how many physical disks, how partitioned, esp. if any extended partitions.
Just to confirm, are you consistent with the terms disk, drive, partition?
Then exactly how you proceeded with the installation of XP, what choices you made with the partitioning, formatting etc. and what you intended to end up with, along with what you now actually have.
Note that it is NOT possible to recover data on a disk that has been changed from dynamic to basic. It is a destructive process.
If you need to recover the data, can you put the disk into a PC running the original OS - or mount it in an external caddy? Win XP doesn't support dynamic drives that are removable.
SD