That board autodetects memory type and there are no restrictions as to which slots they go in.
If each works individually then the problem is a memory mismatch. The first suggestion is Maplin gave you incompatible memory which is the wrong speed, parity etc. The second is that, even if the stick specs are the same, the brands aren't. It happens.
Give us the brand names and specification numbers off both chips just to see if there's anything obviously wrong. But I'd suggest that, if the specs are the same, you ask Maplin to swap the new chip for another brand.
Last edited by ORAC; 17th August 2003 at 02:10.