Hi I wonder if any one can help here, I cant get the ram to run at full speed If i do the PC locks up after 15-20 mins and then i have to press the reset button on the base unit, after i do this the PC will work perfectly fine for the remainder of the time it's used until I power off in which case it will freeze again like before upon first boot. I thought at first it might be a heat problem but as i say it's only the first 15-20 mins on first boot up that is the problem i would guess if it were heat related it would be every 15-20mins not just the first boot up am i wrong ? , I checked temps using the motherboard utility and via bios and all temps and fan speeds are as they should be. I'm currently running the Ram underclocked at 750mhz as this seems to not cause the lockup but surly i should be able to run it at full speed, is this a motherboard problem that cant be fixed or is there any settings that are not right that can fix the problem, I have everything in the bios on auto except for the ram frequency as i said i had to underclock. Specs are below if you need more please ask and if this is in the wrong part of the forum mods feel free to move. Intel core 2 duo 2.66 2GB Corsair DDR2 800mhz N650SLI-DS4 motherboard ( bios updated to latest version) Nvidia Gforce 8800GTs (320mb) running in the PCIE 16x slot 550 watt power supply Xp home SP2 all drivers are latest versions.