Overclocking question

I cant get my A64 3500 stable over 2.42Ghz. Do you think this old memory is the problem or should I look at getting a better power supply. The PSU is a 2 year old Antec 450 and th memory is 2x Cosair XMS Series 512 PC 2700?

I would suggest you try and run the ram at a 133 divider (3:2) to see how far you can go without worrying about the ram. That will tell you how much headroom you have. From your specs it looks like the ram is the likely culprit, but you never know till you try the dividers. Good luck.