Click on the main website of a network or cable channel.
Look for a tab that indicates "free episodes." Each channel has a different set-up which may change when the network redesigns its website. For example, NBC in 2011 had a box just below its main page for full episodes, short clips and "my favorites."
Check cable channels or You Tube for episode listings. Some of the pay channels, like HBO, will show free clips of its material. The NBC-owned site hulu.com has archives of shows from several networks and cable channels. However, hulu, which used to be completely free, now has a month-long free trial you must register for to see most complete episodes. After the trial ends, Hulu charges $7.99 for complete access to its archives.
Follow the on-screen directions to run the program. In most cases, mouse over the screen shot for the program and a small arrow will appear. Push the arrow to launch the video player.