Is there any Php Script for Computer Selling Business
Service Tag Details (Put Service Tag Online to show Product Details, Extend Warranty)
Online Computer Build/Repair Status/Tracking.
Online Driver Download
similar to other PC Websites like HP/DELL Etc
What you are describing is not just A script.
It's a combination of PHP scripts, website and database. Said examples like HP/DELL Etc have spent likely thousands to get their site to work.
While scale is quite different, it's still there and I doubt you can get ready made "it just works for me" script/database off the net. You would also need a server to host said things on too.
Also if you are planning on doing something similar, you would have to also consider how you are going to protect said data in database, especially since some of it might be sensetive information.
Out of the lot, driver download part is likely easiest since that just has some drop-down boxes and end result which then just list the downloadable drivers.