My dell plex gx620 will turn on make some weird buzzing noises and stay on but it will never display anything on the monitor and there is nothing wron with the monitor

Motherboards use signals a radio signals to communicate across them. Some on board soundcards pick these signals up. Try purchasing a better sound card. This might eliminate some of those on board noises you are hearing. Hope this helps.

Try pressing F2 or F11 during boot up and go in to the bios. You should be able to adjust the power settings in there. If that doesn't work, use the control panel from within Windows, go to 'display settings' and change the monitor sleep settings there.

Does anything ever post on the screen when you hit the power button?

Maybe the monitor is bad or the video card inside the computer is bad. Normally if the video card is bad the monitor will display a message of No Signal. If you are getting no message then I think your monitor is bad. To isolate the problem you need to put another monitor on the computer.

Borrow a monitor from a neighbor, friend, family member or co-worker and connect it to the computer. If the Borrowed Monitor displays and works, then your original monitor is bad. If the Borrowed monitor does the same as the original monitor then your video card is bad.

do the following 1.check if the monitor power cable is fixed good.
2.try to connect your cpu to another monitor and see if its working.(if it works no prb with the video card else prb with the video card)
3.if your video card is good .then there must be a prb with your monitor a little soldering will fix it !!!

Replace you video adapter

http://support.dell.com/support/edocs/systems/dim9100/en/SM/adtshoot.htm#wp1054146

just see if this applies to your issue, repost if you need more help

HI there Stephen,

Your Dell Optiplex GX620 has four memory slots which can accomodate a maximum of 4GB (DDR2). For the full information you can click the link below:

http://www.dell.com/us/en/dfh/desktops/optix_gx620/pd.aspx?refid=optix_gx620&cs=22&s=dfh

Please let me know if this answers your question. Thank you for using FixYa.

Try to reseat the memory of the computer. Remove and put it back in and check if it will work. If not, and if you have known good memory that you could try it with, then use it. If that works, then you have to replace the memory.

The first thing to check would be the CMOS to see if there is a setting for "case intrusion" or something to that effect. Some computers have sensor that goes off the computer's side panel is opened. I believe this can be disabled in the CMOS and/or it's just a wire connected to the motherboard that can be disconnected.

It could also be an important fan, like the CPU fan, isn't spinning fast enough which may or may not lead to an over-heated CPU.

Also check to be sure all the memory sticks are firmly seated.

If it doesn't look like any of those it could always the the power supply. See if you can borrow one for a little while for testing purposes just to see if it works.

If none of those pan out I would say call Dell support and see what they say.

send me the PPID Numbers of both monitors, (20 digit serial number) and I'll see if I can find out anything about the monitors that is different.