The best place to find drivers is from the manufacturer:
http://www.samsung.com/support/
Download Drivers
Go to the website of the manufacturer and select your model (this is usually done in the Support section). You should have the option to download drivers for your model. Download the driver(s) and follow the instructions to install - every computer is different so I can't give you exact directions. You can also try using Windows Update to get drivers - it's located in the start menu.
Update driver for hardware that isn't working properly:
http://windows.microsoft.com/en-us/windows7/Update-a-driver-for-hardware-that-isnt-working-properly
What to do when a device isn't installed properly:
http://windows.microsoft.com/en-US/windows7/What-to-do-when-a-device-isnt-installed-properly