|This chap goes through all the issues relating to various windows (XP not the least) in terms of changing components various - the motherboard especially. This particular area/link deals with your situation perfectly…|
If you have an OEM installation originally - it came with recovery disks and/or partition… likely you will not be able use that approach - see above link for more on this.
If you had an non branded OEM disk (i.e. you built the system yourself and purchased an OEM XP disk not tied to a given manufacturer - Dell, HP etc. - to do it…) then "possibly/possibly" you can use that to run a repair installation. But again I defer to the info. in the link above…
The principal difference. between full retail and a non-branded/badged OEM disk is that M$ would provide some support to users of the retail; OEM vendor had to supply support to the end user. Also the OEM is tied to actual motherboard, and less rigidly so to the HD… once you have activated the XP installation. Which having said… I have changed a drive or two in the past and had no problems getting the rebuilt XP re-activated - on-line and/or over the phone.
Michael Stevens "how to things various" are very detailed and specific… I find them a very useful resource.
These two links discuss it more from an "I'm in trouble and general chat approach" on - one here in days gone by and the other from another forum: but worth to read nonetheless?
Retail and OEM full installation disks are around for very few £££/$$$ on line (eBay/Amazon etc.) and many computer fairs and clearance houses.
But again have a read of the Michael Stevens info as he is much more knowledgeable about it all than am I!
Also - to repeat.. safeguard your personal "stuff" on the HD as is; via another working system (obviously) - as advised n my earlier post here.
I would also encourage making an image of your HD as is - as MS suggests too; and keep it safe… Ensure it is a "true image" that includes any and all "hidden" partitions as well (those hidden partitions are usually used as part of a built-in recovery process - with or without additional recovery CD use).
I have Acronis; many like EaseUS products; and there are others too.