Have a great TV and a computer hard drive loaded up with movies and you want to know how to watch movies from your hard drive on your TV? There are a number of easy ways to do it, so you're in luck! You can go down a few different roads, depending on the equipment you have available. For example, if you have a PlayStation 3 or and Apple TV box (among a few other options), you can wirelessly send your movies from your hard drive to your TV. Some TVs have the ability to play movies and music from external media (such as a hard or flash drive). If these don't do it for you, there's always a few more direct options!

To watch movies from your hard drive on your TV, you will need:

Computer hard drive with at least one movie
TV

You will also need (in order of most to least reliable and compatible):

Method 1:

A computer with audio/visual outputs that match your television. Preferably HDMI, though DVI or VGA outputs will do as well if your television allows separate computer sound input.
A cable of appropriate length for your setup. One HDMI cable will do, though if using DVI or VGA, an 1/8" audio cable is required in the same length.

Method 2:

Playstation 3, Apple TV, Slingbox, or other device capable of streaming movies from a separate source
Internet connection for each of your devices

Method 3:

Flash drive
TV that supports external media through USB

Picked your method and ready to start watching movies from your hard drive on your TV?

Method 1:

With your computer and television off, connect the computer and television using the appropriate cable(s). If you have an HDMI connection, use only the HDMI cable. If you have VGA or DVI, run the cable to the TV, then run an 1/8" audio cable from the headphone port on your computer to the Computer Audio Input port on your television.
Power on your television and switch the input to the port you just connected.
Power on your computer. The computer will treat the television as a computer monitor, so in the display settings on the computer, configure the system to duplicate your display or to display only on the television. Consult your owner's manual for specifics related to your operating system.
Play the movie as you normally would. Play in fullscreen mode and it will be just like watching a DVD!

Method 2:

Because of the huge variety of equipment and setups available, consult your user's manual for your streaming device.
If you use Windows 7, you already have most of the system pre-configured. Other operating systems may require more software, depending on the device you use.
Note that you may encounter strange compatibility problems. Apple especially is notorious for what it will and will not play.

Method 3:

Copy your hard drive movies to your flash drive.
Insert the flash drive into your television's media USB port.
The television should auto-display a menu. Select your movie and enjoy!
Again, consulting the television owner's manual will help smooth any problems, though you can expect to run in to an incredible amount of compatibility issues.