A mind of its own

Question

monitor wont come back on when cpu is shut down most of the time i hear a click and have a flashing green light and a blank screen or the no signal light just keeps on flashing sometimes i can turn computer off unplug both cpu & montitor turn monitor on till get no signal showing hook up monitor and then cpu plug turn on computer and after afew times this works but then i have to use my XP disk to boot up monitor and voard work traded them out to check and they work just fine till i put them back in my new computer this couldn't be due to a motherboard change i just got a asus a7v333-x motherboard someone gave me to reeplace the one that went through katrina i had no disk for it for p4 its slow and pauses alot just can't get it right asus not beeing alot of help this time the cpu was turned off and its bee three days and i cant find the right combo to get it back on when i justrestart every thing seems to work monitor comes on up and dont need to boot with xp disk excepet now i need this thing for work katrina has sure put a hurting on my work wife is an artist and i print stationary and trying to get us back online so any help greatly needed and thankfull