I just added another 4GB of ram to my PC for a total of 8GB but as I type this, the task manager is showing me 277MB of free ram with there is 5307MB of available ram. What is the difference and which is preferable? I'm not using a page file so I don't want any problems with my system.
It's advised to leave the page file active. Many programs and situations utilize it and software could even fail to function, regardless of the amount of installed RAM. Also, if your pc ever crashes, it will be impossible for it to create minidump files to analyze.
Windows 7 has the best memory management scheme of all Windows OS to date, so you need not worry about how it is handling things.
Free ram means space that isn't being used at all. Available means space in use that can reallocated as soon as the OS decides it needs it to be.