is an .exe file, you should be able to just click it and it will self-install. If the file is a .zip file, you will need to unzip it to a folder by itself and look for the setup.exe type file to click instead.
If the file is a .zip file and after extracting it, there is no setup.exe type file to click, you can go to My Computer/Printers (or Control Panel/Printers), right click your printer listed there, choose Properties, and update/change the driver there (could be on the Advanced tab or elsewhere depending on the windows version you have)....then browse to the folder you have the printer files in when it asks where to look for the driver.
My floppy disk for installation got damaged so I can not use it to install my printer, so I went to HP.com and downloaded the installation info. But now that it is on my desktop I don't know how to load it to use the printer. The printer is color but it comes out black and white and the print is distorted. What do I do?