My dell gx260 ligth come green if i turn it on but for a few mins time it turn orange why
Do you mean the monitor's power light starts green and then turns orange when you turn it on? Most monitors will go to a power saving mode when they do not get a signal from the computer.
The Dell GX260 has a green power light when on. When the computer is off, the light is off. If it is green and blinking, then the computer is in a power saving mode.
Diagnosis: start with the obvious: is the monitor cable plugged into both the computer and the monitor (if not permanently connected to the monitor)? Are you connected to the active port? (You can add a video graphics card in most desktops. The motherboard video port usually needs to be disabled to use the card ports. If you plug in the monitor cable to the disabled port, it won't work.) Is the monitor set to the correct input? (This applies if the monitor has several ports. In that case, there will be a Source or Input button on the monitor.) Is the computer on? The GX260 has the power button on the front. (Other computers have the power button on the top.) There is also the power supply switch on the back which needs to be on.
Next try a different data cable between the monitor and the computer (if you can). Try a different monitor. If a second monitor works, than the monitor has a damaged main board. If the second monitor doesn't work, then the video graphics adapter has probably failed. Replace the add-on card, if in use, then boot in the safe mode to remove the old graphics driver. Then install the correct driver for the graphics adapter.
Note: the computer and the monitor should both be off when you connect the cables. Then turn on the monitor first and set it to the correct source before turning on the computer.)
I hope this helps.