Question : Problem: Upgrading a motherboard with an existing hard drive without OS disk

I would like to know how to configure a new motherboard to my old hard drive . We have misplaced the Windows XP disk. I have done it before using the Repair option on Windows but without the disc have no idea of what I should do. I was told that to do Repair from Windows, I must have the disk that was used on the existing hard drive .Could anyone help me with this issue? I would be very grateful for a reply.

Answer : Problem: Upgrading a motherboard with an existing hard drive without OS disk

To make a repair install go with a different CD works within limits:::
If you had an OEM DELL XP CD then you need an OEM Dell motherboard and CD. [Same with HP and maybe others.]
If you had a regular retail XP CD then that's what you need. [motherboard doesn't matter]
If you had a non manufacturer specific OEM XP CD then that's what you need. [motherboard doesn't usually matter]
[That's why everyone is asking what the hardware is.]

You can use any same part number [not 'key' -> part number] XP CD to do a repair install.
You can even do a fresh install so long as you change the key to what's on the case before you do any activation or updates.
Worst case is you have to call Microsoft to get it reactivated.

Frankly I'd find the CD or borrow a correct version and do a fresh install, fix the key, then call MS if you have to.
Fresh installs on new hardware work tend to better [or at least less chance of problems] then repair installs.