My usual disclaimer: I'm not an expert at anything.
By process of elimination, since the 4GB stick shows the same readings in both slots, it would seem logical that the 4GB stick and both slots are good. Just for clarification, you mentioned that, "From the start of getting this PC it was constantly Freezing or BSOD'ing and the only thing I have found to do to make it usable was removing the 2GB stick..."
If you use only the 2GB stick and install it in slot # 1, does the computer work? If no, I think it's safe to say the 2GB stick is bad.
In the category of personal opinion, RAM prices are pretty low right now. You could get a matched set of 8GB (2x4GB) for less than $40. I have a Sony Vaio that also came with 6GB (1x2GB and 1x4GB.) It had similar issues to what you've experienced. When I upgraded to 8GB, those problems went way.
2nd dislaimer: I have no personal affiliation with Crucial and offer this for informational purposes only.
I upgraded to Crucial
. Most of the memory sticks I've seen are rated at 1.5 volts. These sticks are 1.35 volts. Lower voltage usually means cooler temperatures. But I bought the RAM about a year ago and paid almost $60. So if that 2GB stick doesn't work, I'd really consider a matched pair from any reputable company.