How do I get quality sound from my PC to my Home Theater?

You've got a few options, but this depends on your computer and its capabilities as well.Depending your computer's sound card you may have an optical output for surround sound. This is on many newer computers with media capabilities. If not this is something that you can purchase for $30 - $300, depending on how much sound control you would like. What a new sound card will offer you will be sound controls, and higher quality outputs than a standard sound card (typically just a speaker output which is a headphone jack connection).If you don't want to mess with installing anything inside your computer there are numerous USB soundcards that you can get. These will connect to your computer VIA a USB connection and will give you many options for connecting to your home theater as well.Go to one of your local computer super stores, or check out amazon.com for sound cards. Look at both USB and internal cards. The only drawback to internal is that you will have to install it inside the machine - which you may or may not be able to do. One of those stores can install it for a nominal fee as well.If you don't want to mess with anything mentioned above you can just simply connect a high quality RCA to Mini cable from your computer to your stereo. Its a cable with a headphone jack at one end and, left and right audio cables at the other.

I hope this helped.

How do I get better sound out of my XBOX 360 through my DVD built in sound system without an Optical Input?

When it comes to Home Theater systems with DVD players built into them, this tends to be the number one complaint. Although you don't have an optical input on the unit, you do have the analog audio inputs (Right , White ) which you can connect the XBOX 360 to. It will not produce the 5.1 surround sound that the system is capable of, but it should have a surround mode for gaming, or general purpose that will make the gaming experience more complete. If you want to enhance the sound even more check out upgrading the Audio/Video cables to Monster Game Cables from Monster Cable, they will maximize your picture and sound to its best capabilities. Also if you want more of the surround experience use the Level settings on the system to raise the level of the Surround Speakers so that there is more active sound from behind you. If it really gets down to you wanting the optical input, you can switch out the receiver, and more than likely keep the existing speakers, or switch out the speakers as well since you have the wires run through the wall. But if you do that you will either end up using the XBOX360 as your DVD player, or purchase a DVD player as well. There are some really good HTIBs out there now for under $500, one in particular from Sony, comes with an up-converting DVD player, and HDMI connectivity on the receiver for future use as well.