What should I do now

I dropped my laptop. It broke.

 I bought the identcal model laptop on ebay. It works. I moved my old WD HD into the new machine…I just get a blining cusor -won’t boot into WinXP

I put the HD in an external case and hooked it to another  PC.

I can read and write to it.

Should I move on to Windows XP repair or do I need to run a WD utility first?

Hello,

Try running the XP repair first. In case you are not able to repair the drive you will need to write zeroes to perform a clear Windows installation. For that you will need the WD DLG tool.