brown spots

Video As you can see there are some black spots on the screen. Normally i don't notice them but when there is something bright i can see them and its annoying. The monitor is an old LG M2250D . Can someone help me?

I tried to turn on my pc after a long time and it doesn’t work, changed bios battery to no avail. Tested with and without certain hardware no difference. Symptoms: Turn on pc, fans spin and turn off after a while, repeat ad infinitum, no led lights on front I detect brownspots on the two...