If You Are Up The Operating System On A Computer Why Would You Need To Update The Device Drivers?

Operating system is a device driver for motherboard and processor. Nowadays, sound, LAN,  and some other devices are built in with motherboard. That is why we don't need to reinstall them, as windows automatically installs these drivers. Obviously, you will have to install other hardware which is not built in.

Sorry taimur that's not quite right. If an operating system (BTW - which?) on booting starts trying to install device drivers and usually quits with an error. This is not dependent on onboard devices or otherwise and usually indicates that the device in question is no longer recognised. Which means that either the device is defect or the driver. Another cause can be that the operating system on shutdown is not writing back to disk correctly and is therefore losing its device and driver database. Try updating the device driver with the latest version. If this doesn't work you may have to reinstall the operating system to solve the problem.