Hi. I have just build my own PC and installed Windows Vista Ultimate 64-bit. I have 4 RAM slots available and into the 2 yellow slots I installed 2 Corsair 2GB memory cards. Everything works fine.

However, I then decided to increase the memory further, ordered two more of the same memory cards, but after I installed these the PC will not boot up. I switch on, the fan briefly makes a noise, then the computer stops.

Any ideas please?

Thanks.

Go into your bios and manually adjust the voltage ratings to the manufacturers recommendations. Don't let the motherboard do the auto selection.

Excellent! Thanks.