Hello Micheal, After re-installing windows, please ensure to install the drivers in the correct order. It is very important for the computer to function properly. Please click here to get the drivers for Dell Precision 390. Hope this helps! 
I am about to do a clean install with Windows XP Pro on a Dell Precision 390 what are the bare essential drivers i will need for the machine to run properly, and where do i get them? Thanks!
After Clean install what drivers do i need for a Dell Precision 390