A lot of laptops don't come with buzzers unfortunately. H
Have you tried turning the PC on with only one stick of RAM plugged in?
Try plugging the laptop into an external monitor, if there is an output on the screen then the problem is most likely to be related to the laptop screen or cable.
Look at the screen carefully, can you see even the shadow of an image? It may be that the backlight on the laptop screen is faulty.
It might be worth removing the DVD drive and hard drive to ensure that they're not causing an issue (it sounds strange, but peripherals like these can on the odd occasion cause a problem).
If none of the above work, then the problem is likely to be the CPU, motherboard, or graphics chip, all of which would require a full replacement motherboard, and is probably not economical as a repair.
Hope this helps.