You can do it, for example, during the install of Windows.
Near the start of the Windows install you are asked where you want Windows installed (whereabouts on the hard disk), and near that point you can specify if you want the hard disk formatted.
NOTE EVERYTHING IS DELETED OFF A HARD DISK WHEN IT IS FORMATTED.
everyone is in a very strange mood today!
if you format it you loose everything .... not quite true .... you'll still have your savings ... your house, friends, family.
if you threemat it it's quicker
and if you laundramatt it ... it will smell nice....
and if you mess up ... you'll have a doorstop
to rebuild your machine
you need a windows disc (assuming that's what you're using) ... you need a driver disc so get things working correctly ...
you should have got one with the machine .... if not you need to find the correct drivers on the web
alternatively .... you possibly got a rebuild disc which will return the machine to how it came from the factory.
Stress again what is said above.
Finding the software drivers and exactly what the hardware specification is that you need the drivers for is the difficult bit.