Just guessing.... fans run for a reason.... is it possible that your CPU's heatsink is not well seated? Booting/loading an OS is moderately CPU intensive; your breaking the procedure by letting it cool after running BIOS and before loading Windows could be explained by this; shutting down also gets the CPU doing housekeeping. Get a core temp monitor, a decent one is, well, CoreTemp.. :) http://www.alcpu.com/forums/viewtopic.php?f=34&t=137
This is strange, though: "Also every time i turn it off the fans go mental after power down until the switch on the PSU is turned off." The mb fans are controlled by a mb hardware monitor chip, accordingly the mb fans should stop at power down?; the PSU fan answers only to a temp monitor inside the PSU.