I built my rig about 5 years ago, when I first built it the PSU melted after about 3 months, I think it was due to lack of airflow in the bottom compartment and a HDD that the bearings were knackered on and was drawing too much power, I installed a 1kw psu and binned the dodgy hdd and it ran fine till about a year ago, when it started rebooting whenever I did anything a bit strenuous on it, even playing facebook games. I changed the graphics card from an x1950 xtx to the hd 6970 but it was still the same. It runs 2 F@H apps with no problems (it was running them 24/7 till I bought my laptop about 18 months ago). I am going to run ram test on monday to rule that out. I think its probably the mobo at fault but I din't want to buy a new one to find out its not that. Can anyone make any suggestions.