Thanks for the follow up!
RAM in machine was as follows: PC3200 512MB stick (cannot tell brand), PC2700 512MB stick (different manufacturer, cannot remember brand), PC3200 512MB CORSAIR x2.
Earlier, when checking, my method was pull all ram and re-seat the matching pair of corsair, and booted AHT. AHT reported that slot 1 was unoccupied and gave an error. Tried to re-seat, same results. Swapped, problem reversed. Slot 2 was "empty". Removed slot 1. Replaced slot 1 ram stick with PC3200 unknown, AHT refused to boot, memory error. Removed slot 2 corsair, replaced with PC2700, same problem. Swapped, same memory error. Removed slot 2, leaving only PC3200. Booted fine, past AHT test. Put it the "good" corsair in slot 2. Booted, passed tests.
I should have been more clear with swapping them around from previous post. I will be more clear in future posts
Typically, ram I have laying around was mem checked before static bagged, usually in memtester for several burn in passes. It is why I would consider it.
I'm done buying cheap Chinese anything. It usually isn't worth it in the long run. I believe I found reputable source of ram for the system, new. I'm planning to just buy that tomorrow. Good to know I need 4 sticks.
Appreciate the help, GaryN. I really do.