I have a motherboard with a PhoenixBios on it and I'm getting POST beeps that denote Autosize DRAM. The problem is I have no idea what Autosize DRAM means. Can anyone help?

The error you are getting is that there is a failure while accessing, initializing or "autodetecting" the extended memory on your board.
The extended memory is all the memory installed beyond the first megabyte.
Possible causes:
a) defective memory module
b) defective motherboard
c) not well seated memory module
d) incompatible memory module installed (if you just did install one or some).
Normally, you can set your BIOS not to test that memory, but of course, this bypass will not fix the real problem. You will probably see a lot of blue screens then.

OK here is how it all turned out. The RAM chips work fine by themselves (i.e. in another computer), the computer works fine with different RAM but they will not work together. The only thing I can figure is that the board has a conflict with Corsair RAM. I tried the RAM in another HP computer and it had the same problem but I tried it in a third computer (non brand name) and it works fine. I put some non Corsair RAM into the HP computer and it registers the full amount. I was told that RAM has little chips that basically tell the computer how much RAM it should register. Basically I can only figure that the mobo that HP puts in their computers doesn't know how to read the chips on Corsair RAM and therefore was registering as having no RAM at all. This is supported by the fact that if I put a second stick of RAM that worked with the HP machine in I could look in the BIOS and see that the slot with the Corsair RAM was registering as empty. Hope this helps anyone who has a similar problem in the future.

Right, the conclusion must be that this HP computer does not recognize the corsair RAM. That was option d), a compatibility problem.