Series of mishaps

Hello,
my name is lyler and my computer would not boot up, kept on repeating the process and indicating that windows would not start successfully. I opted to repair the operating system and had to change the CD ROM. When i put the computer back together the monitor stopped displaying. I put another monitor and still no display, i removed the ram and wiped them then put them back, noe when i start up the machine just beeps once and there is no display.