i hope this helps:
- cross check with other monitors, maybe it's just your monitor having heat/voltage problems.
- try to check for sounds while turning on the pc. sometimes the pc beeps when the computer turns on. here are two links about what these sounds mean: link1, link2.
- since the pc turns on, you might want to open the case and see if all the fans are whirling. you really dont want to see your pc turn on without the fans.
- you might also want to tighten all external and internal connections. e.g, all the wire going into your pc, and all the wares inside your pc. just pushing them firmly might do the job. it might just be lost contact.
- and lastly, you might want to give more details on what's happening with your pc. like the following: does the bios turn on, or does beeps even sound, or does windows load then blackouts, or by the time the indicator lights turns on and still no display.
- if in the case that there are no post sounds, and when the indicator lights turn on and there's no display. what technicians really do about that is check all peripheral hardware's. e.g., remove all hardware, just put the basic things that makes the computer turn on, and if turns on, add another hardware, until you find out that one hardware that caused the problem. (isolate the problematic hardware). there's really no magic trick for these, why? even hard drives (not just memories) cause certain bios (of some build) to fail to load the os on some occasions.
- however, you might want to remove all the excess hardware like if there is an integrated video card on the mother board, try to use it instead of a dedicated.
- you might also want to switch rams to different sockets.
- remove all hard disk/dvd, maybe all sata and ide connections and observe.
- and if the system still doesn't work with only motherboard, ram and (integrated graphics left), maybe there is something wrong with your motherboard, or processor.
perhaps giving more accurate description will make us help you even better.