Why won't my HDMI cord play games on my computer to flat screen?

I'm not entirely sure why it won't but have you tried using the cord that normally connects your computer to your monitor or vice versa? That's the way I have to set mine up as my PC doesn't have a HDMI port. May not be the answer you were looking for but hope it will at least get it working for you. Most TVs in my experience now have an input labeled "PC" or "Computer" and its the same as the input on your monitor, and should just be a plug and play situation where you just have to flip through the input choices till you find it.

The PS3 was developed with HD in mind even though it will work with any TV type. It sounds like your friend just has a regular TV. Game text is indeed hard to read if you aren't using HD resolutions and is probably the only drawback to using the PS3 with a regular TV and/or Composite connection (the Red, White, Yellow cables). Everything becomes more sharper and vivid with HD resolutions. HDMI is the most simple connection to use for HD and is required if you wanna see 1080p. However, Component cables will also deliver quality HD graphics, its just limited to 1080i.

make sure your tv is on the right input and also you may have to go into the video card settings on your cpu and set the output in order to get a feed son