resetting the bios with the battery doesnt always work not to mention its not as easy as the other method , better use the jumper method see your motherboard manual for more info , anyway in my opinion the possible troublemakers are
a) does your graphic card have a 6pin pci-e power connector? if so maybe you didnt connect the cable to it
b) power supply - get a digital multimeter and see these guides
http://www.ochardware.com/articles/psuvolt/psuvolt.html
http://www.driverheaven.net/guides/testingPSU/
report back with the voltages
c) motherboard - check for bad smell also for bad capacitors see examples
http://www.pcstats.com/articleview.cfm?articleID=195
http://home.earthlink.net/~doniteli/index27.htm , even if it doesnt have neither it still doesnt rule it out
d) monitor - take it to a friend and see how it goes there,or attach it to your other computer (if you got one)
e) the ram - test it on a friends computer or on your other computer if you got one (of course make sure the motherboard supports that type of ram before doing it) , also check on the ram manufacturer site for motherboard compatbility and see if it was tested fine with your motherboard
and as for "nothing happend when i took the memory out" - a computer cant work with no ram well ok maybe it can but you just wont see anything ,