As previously stated, current DDR2 prices mean little. Since DDR3 is now standard, DDR2 production is limited. It has become a specialty item. Prices during the prime DDR2 use were half what they are now.
In regards to WIndows: I wasn’t referring to retail installation keys, rather the retail value of an OEM key ALREADY tied to a motherboard. When you purchase an OEM copy from Newegg you have the freedom to install it on any ONE computer of your choosing. With this, it is forever tied to THIS machine. That drags the value down at least half in my book.
Further, you give no consideration to warranties. OEM purchased parts have only the warranty provided by HP. A new hard drive would have 3-5 years warranty. New RAM would have a lifetime warranty. This has only 90 days.