Dell Monitor lights up but doesnt show any pictures?

Fixing monitors isn't something people do anymore. I'm certainly a fan of using old CRTs for the duration of their lifespan, but it's really not financially worth repairing them unless you have some application in which that particular monitor is designed to fit specific equipment (like an arcade game). Fixing a CRT (the type of monitors that are heavy with the glass) is very dangerous. You need to deenergize high voltage capacitors which can carry a charge LONG after the device is powered off and unplugged. The other type of monitors are LCD (flat panels). These don't really have any parts which can be replaced so it's not really possible to fix them. If your monitor is a CRT type and you want to try repairing it as an educational exercise you can still find training materials on how to fix CRT displays. Read the section on safety very well before you take ANYTHING apart.