Keeps entering power save and screen goes black when I turn on PC

Usually, the diagnostic LEDs don't blink like that. But green 1,4 is listed

<ADMIN NOTE: Broken link has been removed from this post by Dell> as a motherboard failure.

You may have to strip it down to bare essentials. Power off and unplug. Press/hold power button on tower for ~15 sec. Now remove all PCI cards, except video card, disconnect all drives except boot hard drive, reseat RAM modules in their slots. Check the power cable connection from the power supply to the motherboard and connectors to the CPU.

Then remove the motherboard battery and press/hold the power button for ~30 sec. Reinstall the battery (right-side-up!) and see if it boots now with only mouse, monitor and keyboard attached.

Ron

Q. I have had to leave the PC on 24/7 to keep it working.  Will it crash if I continue doing that? Please answer.  Not sure what you mean by "crash". If you mean the hardware fails, that's probably not a huge issue. Heat and power surges are your worst enemies. But you can always set the power settings in Windows to turn off the monitor, and stop the hard drive after a certain period of no use, which will help and save energy. A good surge protector is a good idea too. If you mean Windows crashes, the longer Windows is run between reboots, the possiblity of a software crash increases somewhat. Windows and other apps accumulate temp files and other junk which can contribute to a crash. When you reboot those files are usually deleted so there's less junk.  Q. Is there a chance that the diagnostic lights are not mis-indicating the problem? The LEDs aren't always definitive. There are many instances when a user gets an error code that's not listed in the error code table for that model. So that's when you have to strip it down to bare basics to see if you can ID a faulty piece of hardware. Q. I tried to run Dell PC Checkup from the systray -- and that's not working, it's stuck and cant close!  Dell is screwing up:) That could be anything. A software glitch, bad sector on the hard drive, virus/malware infection.... The first way to fix that is to reboot. But since you can't reboot, you'll have to deal with the hardware issues first.  So strip it down and see what happens. If it still won't boot, disconnect the boot hard drive and reconnect the optical drive. Then do the 'battery thing" and see if you can boot from a bootable CD or DVD (eg, your Dell Windows Reinstallation CD or DVD). Thanks RoHe, your reply reflects what I  I read in  the Owners' Manual.  This C521 is abt 4 years old. I'll take it in to have it fixed.

[quote user="ckk0513"]           RoHe, wanted yu to know I called DELL Tech Support because DELL's own proprietary software that came already installed on my C521 Dimension desktop, malfunctioned  got stuck , kept trying to load scan and wd not close. As I said b4, I did not want to reboot  for fear that the screen wd again turn black and enter powersave. The DELL Techie removed DELL PC checkup after she informed me the app had been corrupted by some existing software on my hard drive. Q. Wht might have corrupted the DELL PC checkup software? Q. Is it necessary to have a disk registry cleaner if I already have Microsoft Security Essentials?  Is this disk registry cleaner causing any conflicts?  Shall I uninstall it, if it is unnecessary.   Q.  Could Rogio cause a software conflict to DELL PC checkup? Q.  Shall I reinstall DELL PC Checkup after I resolve the software conflict noted by the online DELL techie?   I want to be sure I have remov ed ALL possible and potential conflicts B4 I reinstall DELL PC Checkup.   PS.  My C521 has stopped the earlier problem of entering powersave and I can now go on the internet.BTW i was able to do this B4 i spoke w?Dell :)  But the diagnostic lights are still showing solid green on #1 and blinking green on #4.  Q.  Am I still at risk for motherboard failure? Q. I have had to leave the PC on 24/7 to keep it working.  Will it crash if I continue doing that? Please answer.  ROHE replied: Not sure what you mean by "crash". If you mean the hardware fails, that's probably not a huge issue. Heat and power surges are your worst enemies. But you can always set the power settings in Windows to turn off the monitor, and stop the hard drive after a certain period of no use, which will help and save energy. A good surge protector is a good idea too. If you mean Windows crashes, the longer Windows is run between reboots, the possiblity of a software crash increases somewhat. Windows and other apps accumulate temp files and other junk which can contribute to a crash. When you reboot those files are usually deleted so there's less junk.  Q. Is there a chance that the diagnostic lights might be mis-indicating the problem? The LEDs aren't always definitive. There are many instances when a user gets an error code that's not listed in the error code table for that model. So that's when you have to strip it down to bare basics to see if you can ID a faulty piece of hardware. Q. I tried to run Dell PC Checkup from the systray -- and that's not working, it's stuck and cant close!  Dell is screwing up:) That could be anything. A software glitch, bad sector on the hard drive, virus/malware infection.... The first way to fix that is to reboot. But since you can't reboot, you'll have to deal with the hardware issues first.  So strip it down and see what happens. If it still won't boot, disconnect the boot hard drive and reconnect the optical drive. Then do the 'battery thing" and see if you can boot from a bootable CD or DVD (eg, your Dell Windows Reinstallation CD or DVD). Thanks RoHe, your reply reflects what I  I read in  the Owners' Manual.  This C521 is abt 4 years old. I'll take it in to have it fixed.

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[quote user="ckk0513"]           RoHe, wanted yu to know I called DELL Tech Support because DELL's own proprietary software that came already installed on my C521 Dimension desktop, malfunctioned  got stuck , kept trying to load scan and wd not close. As I said b4, I did not want to reboot  for fear that the screen wd again turn black and enter powersave. The DELL Techie removed DELL PC checkup after she informed me the app had been corrupted by some existing software on my hard drive. Q. Wht might have corrupted the DELL PC checkup software? Q. Is it necessary to have a disk registry cleaner if I already have Microsoft Security Essentials?  Is this disk registry cleaner causing any conflicts?  Shall I uninstall it, if it is unnecessary.   Q.  Could Rogio cause a software conflict to DELL PC checkup? Q.  Shall I reinstall DELL PC Checkup after I resolve the software conflict noted by the online DELL techie?   I want to be sure I have remov ed ALL possible and potential conflicts B4 I reinstall DELL PC Checkup.   PS.  My C521 has stopped the earlier problem of entering powersave and I can now go on the internet.BTW i was able to do this B4 i spoke w?Dell :)  But the diagnostic lights are still showing solid green on #1 and blinking green on #4.  Q.  Am I still at risk for motherboard failure? Q. I have had to leave the PC on 24/7 to keep it working.  Will it crash if I continue doing that? Please answer.  ROHE replied: Not sure what you mean by "crash". If you mean the hardware fails, that's probably not a huge issue. Heat and power surges are your worst enemies. But you can always set the power settings in Windows to turn off the monitor, and stop the hard drive after a certain period of no use, which will help and save energy. A good surge protector is a good idea too. If you mean Windows crashes, the longer Windows is run between reboots, the possiblity of a software crash increases somewhat. Windows and other apps accumulate temp files and other junk which can contribute to a crash. When you reboot those files are usually deleted so there's less junk.  Q. Is there a chance that the diagnostic lights are not mis-indicating the problem? The LEDs aren't always definitive. There are many instances when a user gets an error code that's not listed in the error code table for that model. So that's when you have to strip it down to bare basics to see if you can ID a faulty piece of hardware. Q. I tried to run Dell PC Checkup from the systray -- and that's not working, it's stuck and cant close!  Dell is screwing up:) That could be anything. A software glitch, bad sector on the hard drive, virus/malware infection.... The first way to fix that is to reboot. But since you can't reboot, you'll have to deal with the hardware issues first.  So strip it down and see what happens. If it still won't boot, disconnect the boot hard drive and reconnect the optical drive. Then do the 'battery thing" and see if you can boot from a bootable CD or DVD (eg, your Dell Windows Reinstallation CD or DVD). Thanks RoHe, your reply reflects what I  I read in  the Owners' Manual.  This C521 is abt 4 years old. I'll take it in to have it fixed.

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I'm not a fan of Dell's PC Checkup so, if it were me, I'd forget about it.

Anything can cause a software conflict with anything. You need to be careful about registry cleaners. They can do more harm than good. If you really must have one, ccleaner is free and used by many people on these forums.

Microsoft Security Essentials is not a registry cleaner. It  protects against viruses, spyware, and other malicious software. It should not be used if you have any Norton, McAfee, AVG or any other security software running.  Have you done a full scan lately?

If you're still getting that LED error code, you might want to reset BIOS. Reboot and press F2 before Windows starts to load. That opens BIOS setup. Copy down all the settings so you'll know how things are configured. Then:

Power off and unplug

Press/hold power button for ~15 sec

Open the case and remove the motherboard battery

Press/hold the power button again for ~30 sec

Reinstall the battery (Right-side-up!) and see what happens when you boot now. BTW: if the battery is more than ~2-3 years old, this might be the time to install a new one. It's a  3-volt CR2032 lithium coin cell, about $2-$3 at discount stores. When you reboot, go back into BIOS setup and make sure all the settings are the way they were before you removed the battery.

Maybe that will clear the error message, in which case, nothing else probably needs to be done at this time.

Ron

RoHe, Ron I carefully noted your advice and will follow through. 

Yes the error conde on the diagnostic lights continues, with 1 and 4 lit up and 4 flashing fast, but hav absolutely no problem now  with how my desktop DELL C521 Dimension is working.

Q.  Yu know that power button right by the search field near the start button at the bottom of the desktop screen -- that says "install updates and then shuts down your computer."  ? Well, it consistently fails to install updates, usually indicating about 16 updates.  If i am missing these updates, isn't that bad for my system? Why is my system unable to install certain updates, but  installs other updates. What could be blocking the updates?

Mind you i don't select these updates, these are recommended Windows updates

Q. In answer to your query yes I scan and defrag once weekly.  Is that enough to do?

Ron, When I get more adept I will follow thru on your advice to reset bios, change battery etc. not yet tht skilful:(

Q. Also, in followup  to your suggestion, can yu tell me if it is necessary to have a disk registry cleaner?  THANKS very much