Ya its 1GB each and both of RAM in 1 PC i'm using has the maximum.

Then set one computer aside and use for spare parts.

I would go with the Pentium 4 board. Celeron processors are slower than standard P4. See here: Celeron - Wikipedia, the free encyclopedia

I would go with the Pentium 4 board

I thought I said that but I see I didn't. I agree, if the P4 is working, use that before the Celeron. Thanks Rich.