check the blink codes, if the blink codes are a sequence of 1 and a long delay. that decodes to the CPU not funtional. it is either the cpu itself that is having the problem or the CPU socket is not working. in that sence you need to replace one or the other.

the power supply has actually shorted out internally. if your familiar with some solder work you can test each and every component.. but time consuming and not worth the supply costs. at that point buying a new one is the easiest and cheapest solution sadly

all NIC cards are replaceable. you just have to obtain the right one. if you go to your device manager and look whether it is Atheros or reltech for example. once you get that you can obtain it from their website or a part supplier.

The most common cause of this is the LCD itself. The odds that it is the graphics card are slim mainly because the graphics card doesn't depict that data stream. Your best bet would be to just replace the LCD.