I've recently started to play around again in my old computer and everytime I start it up I get 3/4 very long beeps I've changed the ram ive also tried to clean the ram ive tried 3 diffrent video cards but nothing. until I decided to change the cpu then the computer starts normally but monitor still won't connect Is it the CPU or the motherboard? pc specs: motherboard foxconn Intel pentium 4 3.2 GHz nVIDIA 512 MB 512 MB ram ddr400