[Solved] No display on new built computer

Hi all. Just finished building my first computer. got it all together and plugged it in, turned it on and there is no display. i had put in second hand dvd r/rw and 3.5 floppy. The cpu fan did not spin when turned on (connected to cpu fan header, (turned off within a few seconds)) but when connected to power fan header it starts ok. I've disconnected the two optical devices and tried again but still the same. Is there something simple i have missed? system as follows:

motherboard - gigabyte ep43 ud3l
graphics - gigabyte 9500gt 1gb ddr2
hdd - hitachi 1tb
Ram - not sure model but is 4gb (2 x 2gb chips) set is no's 1 and 3 slots.
PSU - 2themax 450w
cpu - intel quad core 2.33ghz

Thanks
Dennis

Hi Viper, thanks for info. just a bit more for you. When i bought the mainboard, ram cpu and cooler, and hdd, the guy in the shop assembled the cpu and cooler, and ram into the mb, the then connected it with an old graphic card he had in his shop and ran it up, it got to the mobo setup page. all he did then was unplug his stuff and left me with the partially assemble mb. I have now completed the build, although a couple of months after he had done the test. Would the cmos battery lose all its power in this time/ should i get a new one and replace it?
There are no beeps when i start it. the cpu and graphic card cooling fans run but nothing else seems to happen.
Thanks
Dennis