My dell showing Orange light

Just a warning, I am fairly inexperienced, and I am just answering this because there are no answers. This could honestly be a lot of problems, so please bear with me. I looked up the error light, and a solid orange light means that the PSU is receiving and distributing power. but the PC is not computing the data. This would probably mean the cause of this is the failure to POST. The Power On Self Test checks all of the necessary components on a PC. This includes the RAM, CPU, GPU, and SSD. I see that you have said that you have already changed the RAM, so next, I'd test the individual slots. Take a known working stick of RAM and put it into each of the slots. If this doesn't work, I would check the GPU next. (I would not test the SSD because its failure in my experience has just been a no boot device error, not a failure to POST.) To check the GPU, safely unscrew it from the GPU bracket, press the release switch next to the socket, and pull it out slowly. If you happen to have a low-profile single slot GPU, then you could put in its place, but I am assuming you would not have one. Without the GPU installed, power on the PC. if the power light stays a solid green, then your problem is with the GPU. If not, I would check the CPU. Assuming you have a replacement that will go in the same slot, take off the cooler, replace the CPU, RE-PASTE THE CPU!!!!!, and put the cooler on. Now try to boot up the PC. If it still doesn't work, I would just honestly buy a new PC. If its from 2002, the proprietary parts will be too rare to find well. Good luck on your endeavors!