os in 2 partitions

[smithi]

hi .my os is windows xp sp2
intel(R)
pentium(R) 4 CPU 1.50Ghz
256MB
harddrive is partitioned .os was previously in C:
trying to reinstall xp,   by mistake I put it in D:
now os is in 2 drives.I want to format the C: , having os in D:
when i tried using disk manager deleting C: is not enabled.and also it is shown as SYSTEM and NTFS.
Is it harmful if i format C:,and how can I format it.
thanks in advance 

[patio]

If you format C: then your install on D: will not boot...
This is because no matter what partition you install Windows to it writes certain system files to the root of C: in order for it to run properly.

Best bet is to back up your data ...re-install XP and have it delete/create the C: partition...
You can then safely delete the install on D:.

Good Luck.