In case either if you want to upgrade or downgrade to a new operating system you will need new system drivers . For example consider if your system is presently running on Microsoft Windows Vista and you want to downgrade to Windows XP, then you need to install drivers that are compatible to the new operating system means you should install drivers compatible with windows XP. You can download it from Your system's Motherboard manufacturer or can install from CD-ROM if the manufacturer provides you one. But these are risky jobs, In my view simple job by which you can download these drivers is from websites that provide you with all drivers. One such website is Driverssoftware.com .
Driverssoftware website is hosted with over 3,00,000 from 3000 companies from which you can download latest drivers for your peripherals. You have a choice of over 3000 companies to choose from to download the drivers for your peripherals.