Thanks all for the info.
The reason I asked about the RAM was I heard that the RAM always had to be paird.
So for example, I have slots that would take each one of the sticks shown , however it would not work.
So I was of the understanding that the 2 x 512 would be ideal vs. the 1 x 1GB.
I thought (which could be corret) that I could use the 2 x 512, then 1 x 1GB.
A bit late on the reply but since it hasn't been responded to yet.
From the pic you posted you show 5 modules not 3 -- are they all available for use ? If so then here are the options I would use
1.) Use the 2 Kingston 1GB modules (total 2GB.) DDR2 667 at CAS5 1.8V setting and see if the system works with them -- They would need to be placed in color matched RAM slots on the MOBO so they run in dual mode.
2.) If that works add the 2 Corsair 512MB modules into the other 2 slots ( these are slightly slower rated modules at DDR2 533 rather than 667Mhz. but are usually fairly good overclockers so may work alongside the 2 Kingstons giving you 3GB @DDR2 667 CAS5
If the system will not boot with the 3 modules at DDR2667 remove the 2 Corsair modules and go into BIOS and set to DDR2 533 speed shut down and reinstall the corsairs and see if it boots. If it does I'd still use all four modules even though they are at a slower speed since 3GB. @ DDR2 533 is still better than 2GB. @ DDR2 667 settings.
IF that still doesn't work then just use the 2 Kingstons since they are the faster m\and larger modules of what you have and will give you 2GB.