Dell PC wont turn on

It sounds like something to do with the internal video card. You can try reseating the ram and try that, if that does not work, then there may be something wrong in the internal part not easily accessible

do u see the screen flicker at all when u first turn on the pc, or hear any system beeps anything?
Sounds like it may either be your screen or your video card, but not really enough information to tell. Another option is if you have a desktp monitor sitting around connect it to the video out of your laptop, and look for the function key to switch displays on my acer its fn key f5 but most likly different on yours. If you can get video from that then its a screen issue if nothing you move onto the next step
Ttake out all removable components, the removal cdrom drive, or whatever removable drive is there, harddrive 1 stick of ram if you have 2, and try to start it, the laptop does not need a harddrive or disk drives to boot atleast to your bios post screen. if video comes back on with nothing hooked up youve narrowed down your search a little more. let us know if you get any farther on diagnosis.

Hmm. Similar situation to what our Dell desktop had happen to it. Luckily we bought a laptop a few days before. Though ours started getting blue screens first and then we just let it sit. One day I felt like seeing a blue screen I guess so I went downstairs and turned it on and had the same thing happen :( Oh that's right my geekyness was coming so I wanted to fix it but didn't have a clue what I was doing because I kinda had to solve two issues :( It sits there to this date.

This is a problem with your GPU by the sounds of it.

I think the best way to solve this problem is a new motherboard.