Disable Background Apps?

What antivirus are you running? You really don't need anything but MSE and other antivirus programs can cause issues with playback.

I think you'll need LAN and USB and the CPU/GPU for the system to run.

I would, if you want to run as little background apps as possible.
you can use a program called ccleaner to disable unnecessary stuff on the Tools -> Startup tab
http://www.piriform.com/ccleaner/download
Plus its a really nice cleaning tool if your not familiar with it.

also as recommended by Sammy2 i would try MSE as that antivirus is less invasive and low on resources and for the right price it does a great job
http://windows.microsoft.com/en-US/windows/products/security-essentials

CCCleaner can destroy codecs required for content playback.

There's no reason to use CCleaner to disable startup items. Windows has a built-in tool for that called MSConfig. CCleaner was useful back in the XP days when the registry could get screwed up pretty badly and bog down a system, but from Vista on, that generally isn't going to happen anymore.

Use MSConfig (as mcturkey suggested) or AutoRuns: http://technet.microsoft.com/en-us/sysinternals/bb963902.aspx

Although even on Windows7 CCleaner still finds tons of registry errors. I use it regularly on my main PC to cleanup the registry and get rid of unnecessary files.

David

Another place to look for turning off unwanted features is Control Panel, there is a section on disabling stuff like indexing, media programs, tablet functions etc.

David

It may find tons of registry "errors", but it can just as easily mess things up. The registry is basically just a giant settings file, but as I had stated, starting with Vista, the performance issues that could come from a cluttered registry aren't really there anymore. I'm not a fan of programs that try to "fix" such vital parts of the OS, as I've frequently seen them cause more problems than they fix.

I would definitely not ever run it on what should be a relatively static system such as an HTPC. The most important lesson for HTPC owners is, once it's all working how you need it to, leave it alone! :P

What I have done on all my HTPC's is to set them up with the latest drivers at the time, get everything working the way I want and disable or uninstall any OS features. Once I am happy I usually run a disk cleanup and registry check with CCleaner , then check everything is still working correctly. After that I only update drivers if there is a fix that might affect me. I use my main PC as a test bed for XBMC features and plugins and for testing HTPC related applications so i need to regularly clean up stray files and registry settings. My main PC has an image copy done every month with weekly backups in between.

David

Yeah i know that one can use msconfig to accomplish the same thing but i recommended ccleaner because in my opinion its a little more friendly for a new user, its free and i personally use it on all my systems. I have never experienced any issues caused by ccleaner. and yes i have been running it on Windows 7 and Windows 8 since it does support both OS's. Anyhow I wouldn't recommend something that i haven't tested or is known to cause issues. And yes I do agree that some registry cleaners can break stuff and cause apps to have weird problems but like i said above been using it for years and never had any issues.

Any ways OP now you got choices to accomplish the same thing as they say there is more than one way to skin a cat.