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Dell Optiplex 745 Small Form Factor Troubleshooting

Released in 2006, these computers are highly sought after for their dependability.

The computer will not turn on ¶ 

Your computer refuses to turn on no matter how many times you press the power button.

The power switch is off or the power cord is unplugged ¶ 

The power switch on the power supply may be in the off position, or the computer could be completely unplugged. Check the back of the computer where the power cord plugs in to make sure the cord is securely in the power slot. Next, make sure the switch directly below the power cord slot is set to “On.” If the computer still does not turn on, it’s time to find out if the power supply is working correctly.

The power supply is broken ¶ 

The power supply may be broken. Press the power button. If it begins blinking an amber light, it may be time to replace the power supply. See our power supply replacement guide here.

The motherboard is faulty ¶ 

If the computer still refuses to turn on, there may be an issue with the motherboard. Inspect the motherboard for bad capacitors. Capacitors are the tall cylinders standing up on the board. If the top of any capacitor is domed or leaking fluid it needs to be replaced. Replacing capacitors is difficult and requires skill in soldering. Following are links to Youtube videos for anyone who is knowledgeable in soldering and would like to attempt to replace the capacitors.

Part 1: Replacing Capacitors Part 1

Part 2: Replacing Capacitors Part 2

A CD or DVD will not play ¶ 

The computer functions properly but DVD’s/CD’s are not being read.

The optical drive is broken ¶ 

If your computer seems to be working properly but your DVD's and CD's aren't playing, the problem could either be a bad disc or bad optical drive.

If you try the disc on other computers and it's still not being read, it’s a bad disc and there’s nothing wrong with the computer! However, if the disc isn’t the problem and can be read on other computers, the optical drive may need to be replaced by following the optical drive replacement guide found here.

The computer freezes or screen turns blue ¶ 

Fatal blue screen and freezes can be due to faulty hardware. Following are a few tests you can do to check two pieces of hardware, RAM and hard drive, that commonly cause computer freeze ups and blue screen errors.

The RAM is not connected properly ¶ 

Faulty RAM is a common cause for the fatal blue screen. Download a free and easy-to-use program like MemTest86 to check for errors in your RAM. To be sure that the RAM is broken and not just improperly connected, follow the RAM replacement guide here to ensure it is properly inserted.

The RAM is faulty ¶ 

If you are sure the RAM is properly inserted but still get a blue screen, the RAM may be broken and needs to be replaced. Follow the RAM replacement guide here.

The hard drive is faulty ¶ 

Corrupted files on the hard drive can cause freezes and the blue screen. Use this guide to check your hard drive for errors. If errors are found in the hard drive, then it may need to be replaced. Follow the hard drive replacement guide here.

The computer shuts off randomly and feels very hot ¶ 

If your computer is hot to the touch and/or powers off without pressing the power button, the fan may need to be cleaned or replaced.

The fan is clogged ¶ 

There may be dust and debris keeping your fan from turning properly. Follow the fan replacement guide here to remove the fan and clear out any debris with compressed air.

The fan is broken ¶ 

If your computer still overheats, you may need to replace the fan unit entirely. See our fan replacement guide here.

The computer is making abnormal noises ¶ 

If a moving part happens to break or become warped then it may make noise as it spins around. This part may need to be replaced.

The CD/DVD drive is broken ¶ 

If you place a disk in this drive and it starts to make noise (most likely a clicking noise), check to make sure the disk itself is not broken or warped in any way. If the noise persists, the optical drive may need to be replaced. Follow the optical drive replacement guide here.

The fan is broken ¶ 

If you hear clicking noises when the fan turns on (usually when the computer is warm and starts making a whirring noise), it may need to be replaced. Follow the fan replacement guide here to either remove and clean the fan or replace it.

The hard drive is broken ¶ 

If there are clicking noises coming from inside of the computer (while there is no disk in the CD drive and the fan is not running) when you boot it up, this is likely caused by a defective hard drive. It is recommended that you backup your hard drive immediately and follow the hard drive replacement guide here.


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