Here’s some key things to review:
* Has the memory been recently replaced(Memory only lasts 2-3 Years)
* Has the CPU been recently replaced(CPU only lasts 3-4 Years)
* Have you reset the CMOS
* Have you tried replacing the CMOS Battery(Typically replaceable with a CR2032 Cell Batery)
* Is your CPU compatible with your motherboard(Sometimes a new CPU will not play nicely with your motherboard)
* Are you using DDR2-400(PC2-3200) or DDR2-667(PC2-5300)
Sometimes new components will not play nicely with older systems. Check the compatibility of all of your components.
Generously,
Richard Smith