1) How exactly are you going about it? Follow this tutorial. Driver Install - Device Manager
As for file not being found, its either because you dont have the right driver files or you're pointing to the wrong location.
2) I'm not a fan of Driver genius and similar software. On many occasions it has wanted me to download a driver which is already installed or download an older driver. Best way to update drivers is to visit the motherboard manufacturer's website or the device manufacturer's website, locate the download page for your model, then download and install updated versions. For intel drivers, intel's download page is also a resource.