According to the manual you have 4 dimm slots. Put both modules into dimm 3 and 4 and see if that cures you no boot problem.

Thanks for the suggestion. I just tried it but unfortunately it didn't work. The manual recommended memory configurations seems to say you have to have a matched pair of memory modules in slots DIMM_1 & DIMM_2 before you can use slots DIMM_3 & DIMM_4. When I put them into DIMM_3 & DIMM_4. I just got the same diagnostic lights 3&4 and the computer will not boot. Could it be something to do with a loose connection? I currently I have two 512MB memory modules. If i can't get DIMM_1 to work again if I installed a 1GB memory module would this help speed things up or do you really need to have two functioning matched memory modules for optimum performance (The computer works but it is painfully slow with only one memory card)?

Thanks

Yes you can run a 1G ram module in order to mantain same amount of ram.  Did you try using  ram in dim 2 and 4 or 2 and 3? This might save you purchasing more ram.

Double post, also answered HERE

Bev.

Thanks DCX4EVER. I tried this and it worked :emotion-2: dim2 & dim4 work ok. It looks like if anything is put into dim1 or dim3 the computer will not boot. There must be something wrong with that half of it? I guess this just means that I won't ever be able to have 4 memory modules working, but things are fine with just these 2 working. Big help Thanks.