JeanTech in my personal opinion are PCWorld cheap rubbish that realy are not worth the few pounds you spend on them.
Sorry if that offends you..
Take the PSU back and buy yourself a decent PSU like Corsair or OCZ....
I always say the PSU is the heart of the computer if it fails/overheats it can cause more damage than just a dead PSU....
Your running a dual core CPU it deserves a better branded PSU,your issue is JeanTech PSU,it will run hot and eventualy fail....