I dont know what to do now
So i bought a graphics card for my Dell dimensions 2400 and it also needed a new power supply the power supply was installed and it works fine, i installed the graphics card and i disabled my graphics controller the graphics card is installed correctly because it said in device manager. When i plug my monitor into the graphics card it doesn't go on but the monitor is not searching for a signal like when its unplugged the graphics card is Verto NVIDIA GeForce 8400GS. And the graphics card fan is on when the computer is on. And the monitor is the original one with that computer its one of the large ones (cant think of the name for them).