Board logo

PC Not Working - Help Please
John P - 1/12/16 at 02:09 PM

This morning I went to turn my computer on and found the power light was already lit but when I turned the monitor on there was just a black screen with a brief message that there was no signal and the monitor was going to power save.

I don't have a spare monitor to try so I connected the existing one to my laptop using the same cable and it seems to be working fine so presumably the problem must be with the PC.

Unfortunately it's a second hand one which came from my daughters firm so I don't really know it's history but it appears to have on-board graphics plus a separate graphics card which has a DVI-D connector into which is plugged a cable which has two VGA connectors and originally supported two screens when it was being used at my daughters firm. I have a VGA lead plugged into one of these and this set up has been working OK for some months.

I have also tried plugging the monitor into the “on-board” graphics connector but there's still no image on the monitor.

The computer is a Dell Optiplex 755 running Windows 10.

Out of interest I can't now turn the computer off as pressing and holding the power button does seem to cause it to go off but a few seconds later the light comes back on and I can hear the fan running.

With no screen I'm at a loss to know what to do.

Any suggestions how to proceed?

John.

Chris_Xtreme - 1/12/16 at 02:37 PM

just a quick thing - have you taken the mains out the the pc to make it fully turn off?

then back on again?

my only real other thought is to take the extra graphics card out - if it has gone bad, it may still be blocking the onboard one from working.

if you are not getting the first dell / bios screen then it isn't going to be a harddrive / windows issue, i shouldn't think.

monkeyarms - 1/12/16 at 03:06 PM

I see you are focused on the video side of things, but one of the main cause of failure with older PCs can be the PSU. They tend to be of very low quality. We see it a lot at work with people bringing in their own Pcs with similar problems.

Unfortunately it can be a pain finding a replacement.

james h - 1/12/16 at 03:18 PM

I had a similar issue with my old laptop after I had to take it apart to clean out the fan. I hadn't put the RAM in properly, got a blank screen but it sounded like it was running. It should be easy and cheap enough to replace (if that's the issue).

gremlin1234 - 1/12/16 at 04:23 PM

for the optiplex 755
there should be some status lights on the front, what do they do as the machine fails to start?
http://f5k.wikia.com/wiki/Front_Panel_Lights_-_Optiplex_755,_960,_980

tajgreidotu - 1/12/16 at 05:12 PM

quote:
Originally posted by John P
This morning I went to turn my computer on and found the power light was already lit but when I turned the monitor on there was just a black screen with a brief message that there was no signal and the monitor was going to power save.

I don't have a spare monitor to try so I connected the existing one to my laptop using the same cable and it seems to be working fine so presumably the problem must be with the PC.

Unfortunately it's a second hand one which came from my daughters firm so I don't really know it's history but it appears to have on-board graphics plus a separate graphics card which has a DVI-D connector into which is plugged a cable which has two VGA connectors and originally supported two screens when it was being used at my daughters firm. I have a VGA lead plugged into one of these and this set up has been working OK for some months.

I have also tried plugging the monitor into the “on-board” graphics connector but there's still no image on the monitor.

The computer is a Dell Optiplex 755 running Windows 10.

Out of interest I can't now turn the computer off as pressing and holding the power button does seem to cause it to go off but a few seconds later the light comes back on and I can hear the fan running.

With no screen I'm at a loss to know what to do.

Any suggestions how to proceed?

John.


First of all unplug the computer.

Plug it again:

1)if the fan of the PSU is slightly working but the computer does not start - replace the PSU or internal fuse

2)if fan is not working at all, unplug, open the case, take out the external video card and connect the VGA or DVI to the onboard port. plug and start again and should work.

Good luck!

benchmark51 - 1/12/16 at 05:30 PM

My Dell Optiplex went iffy when some of the usb ports wouldn't work and the mains input socket broke. I bought a used one on Ebay for about £20, just had to fit my hard drive in it and it was up and away.

John P - 2/12/16 at 05:26 PM

Thanks for all the suggestions.

I followed gremlin1234 suggestion and checked the lights on the front (hadn't realized they were fault codes). These indicated a memory problem and suggested removing all the memory cards and replacing them one by one until the fault re-appeared or the PC was working.

This worked fine and all now seems to be OK with all four of the original memory cards back in.

Can't really understand what happened but I'm pleased it now appears to be working although I'm still a little concerned.

Also now worried that I have never really backed up my data properly. Any recommendations how best to do this? Are the on-line solutions any good without paying too much or would I be better off with a portable hard drive?

John.

Chris_Xtreme - 2/12/16 at 05:34 PM

personally I do both. I use acronis to take an image of my machine to local external harddrive and also use acronis to upload files to the 'cloud'

works really well for me.

if you care lots you can also use another hd inside the machine and use file backup in acronis or windows built in to every x minutes backup the folders you care about.. this will even keep easily accessible to you previous versions.

google drive may work for you too, or there are many others for 'cloud' backup. the cost model depends on how much data you want to back up.