Dell optiplex gx520 1,3,4,&battery lights is stay working

SOURCE: Dell optiplex won't Boot-up.. Orange light on motherboard

its going to rather your power supply or your motherboard has died, id try a different power supply first

SOURCE: My Dell Optiplex 170L

If I recall correctly, we had this happen when we first got our 170L's. The problem was the actual on/off switch on the unit was defective. Ours were still under warranty so Dell replaced the units. If you have spare 170L's you can pop the faceplate and swap on/off switches to see if that corrects the issue and then order a switch from Dell.

SOURCE: Dell PC Desktop Optiplex GX260 Doesn't boot

Open up the case and remove any add in cards and memory modules. Try to start up by adding these back one at a time until the unit stops booting normally. The light combination is not one recognised in the user manual so I am guessing you have a non-descript fault with one of your components. Be careful when you open the case as to not disturb the ribbon to the motherboard which controls the power, I have had a very long experience trying to get one of these reconnected!

SOURCE: Dell (ie optiplex 330) would not boot with the orange light on

Do you have a lot of accessories plugged in? They may have overloaded the power supply and if this is the case you will need to buy new power supplies. If this is not the problem, check to make sure that the computers have plenty of ventilation in the back. If they don't, they may have overheated and melted quite a few different components.

SOURCE: hello, i have a dell

check ur battery dude.....ur battery life must have gone!!!!!!