Power off issue for GX280

The only thing I can think of is that you might have some muck under the keyboard. See if you can get someone to clean out the inside of your keyboard. Hope this helps.

Dell Support > Optiplex GX280 Desktop PC > User Manual,

http://support.dell.com/support/edocs/systems/opgx280/en/ug/tindex.htm

I chose the Mini-Tower model because the following information applies to all models;
Small Form Factor (SFF)
Small Desktop
Desktop
Small Mini-Tower
Mini-Tower

Computer and Software Problems > Troubleshooting Tools and Utilities > System Lights,

http://support.dell.com/support/edocs/systems/opgx280/en/ug/tools02.htm#wp1114432

Now scroll down. What do the Diagnostic Lights indicate?
Post back in a Comment.

Regards,
joecoolvette

When your computer emits beeps when you power on the computer, it's usually means that you have a memory issue. Try re-seating the memory modules and power on the computer. If you have more the one module, insert one at a time and power on the computer. The other issue is if that model supports 4 gig memory.

Hi there, For the GX280, you don't use a jumper to reset the BIOS password. You can reset the BIOS by pulling out the motherboard battery. The battery is on the opposite side of the external ports, and is flat and silver.
Power down and unplug the computer, then remove the battery for 10 seconds. Put the battery back in, then power up the computer. There should no longer be a password. If it is a Windows password you are talking about, you will need to reinstall Windows. Please let me know if that is the case. Alex

It's a pretty common issue with the 270 & 280. More times than not it is blown capacitors at the root of the problem. Replacing the caps is simple if you know how to solder very well & makes for an easy fix. Also, make sure you're pushing enough power through your supply.

Check your power settings in the control panel, check that the keyboard has no buttons that can cause shutdown.
Check that your fans are working, and then check the event logs to see what has been happening...

Hi, sounds like a crash, do you get any report messages after reboot? Try starting in safe mode; press Del button during initial bootup, once in safe mode you can reset to a time before the problem started. Hope this helps, if not come back to me?

Could be several things; bad memory, bad CPU cooler etc.

start windows in safe mode by shutting down the computer...then start the computer up and quickly tap on the F8 key...select safe mode....this will get you past the login where you can go into the control panel and go to "Users" and then change the password for your user ID

It happens because the power supply is overheats and computer goes to standby. The power supply is 160w or lower. Specially it will happen if you put more devices in such as video card or sound card. So the only solution you have is to place a small 1or2 fans toward the power supply to make it cooler. And 1 more thing the power for the fans should come from other sources.