Rebuilt a PC using XP and all the drivers.

On swt on it takes an age to get past the first windows loading screen, than another while to get past loading windows. I've defragged and run XP in repair mode but it still takes ages to get to the user log on screen.

It also takes an age to close down.

Once past the user log on I get the performance I expect from the SPEC

Any ideas what's the prob or should I just blow the install away and start again.

Try clearing out all the spyware and adware using Advanced System Care. There is a free version that cleans out all this stuff. It's amazing what it can do. If you run that program and you still have a long shut down and start up, then clear it out and reload everything all over again. It's just whenever you go on the net you pick up stuff that slows your whole system down. You never know where that stuff is hiding.

Also CCleaner cleans up all the leftover program install stuff. Run that also.

Have you checked all your startup items?
-strat, run, type msconfig - enter
-go to startup tab and see if there are programs that are there that maybe you don't need to start with PC

Also in this post, links 3 and 5 will make a difference is 'speed' and overall performance
https://www.askmehelpdesk.com/computers-beginners/frequently-ask-questions-about-computers-233870.html