You are working on a system that is 10+ years old. I highly doubt there is any tech support available for it.
Many BX boards had problems running with all 4 memory slots full. It was a toss up whether the system would boot/be stable with all of the slots filled. Some manufacturers install seperate buffer chips on the motherboard to enable running with all slots full, but to my knowledge Intel branded motherboards never did.
That PIII CPU won't make it to 1gig. The best you can really hope for is 667 (assuming it is currently a 500), and that is running the memory/FSB at 133.
BX was a great chipset, likely one of the best/toughest ever made. "Was" is the keyword.http://homepage.hispeed.ch/rscheidegger/ram_bx_faq.html
I am a retired Ford tech. Next to Fords, any computer is a piece of cake. (The cake, its not a lie)
3770K @4.5, Corsair H100, GTX780, 16gig Samsung, Obsidian 700 (yes there is a 700)