lap top wont boot

Hootsmon

Is there a number of obvious reasons why a newish, hardly used LT suddenly wont boot.....?

I gave it to a guy who "sorted it" only for it tae act up again a few days later....I would just like tae ask him "did you check for such and such?" before I throw it in the bin....

wibble

What make and model is it? What operating system?

Hootsmon

dell inspiron W7

chillidoggy

I thought this was going to be another Hoots cartoon.

Hootsmon

chillidoggy said:

I thought this was going to be another Hoots cartoon.

bodhi

Does it power up at all?  Any errors or messages displayed on screen?

Hootsmon

just a big blank.......he has sorted it but it just reverts back after a day or two....

revsorg

A newish Dell - warranty? 

Funkfingers

hootsmon said:

just a big blank.......he has sorted it but it just reverts back after a day or two....

Is there a flashing cursor line in the top left of the monitor screen?

Any "beep" code signals on power up?

Something as dumb as a BIOS battery failure could leave the machine unable to find its own internal HDD.

It might be worth inserting a legitimate Windows Install disc into the optical drive.

quarky

hootsmon said:

just a big blank.......he has sorted it but it just reverts back after a day or two....

A crappy video driver then? Could you look at a different video driver, maybe from the manufacturer?

bodhi

Does the Dell logo screen appear at all when you power it up?

Emp_Fab

Please answer exactly and precisely the questions being asked or this could take a lot longer than it needs to!

Computer fault diagnosis and imprecise answers are not good bedfellows.

57Deluxe

remove battery, remove PSU and cable. and keep your finger on start button for 30 secs.

Replace items and attempt restart

Emp_Fab

@hootsmon Are you thinking about it or have you thrown it out?

Hootsmon

the guy that was supposed tae fix it still has it Emp

Danny1969

When you say blank screen I imagine your not even see'ing the Dell logo .... in which case do you get a caps lock light when you press caps lock ..... if neither then the machine isn't posting. 

My moneys on bad BGA joints  ....... you can fiddle about and get it working again, you can reheat the chip but it won't ever be 100% reliable unless you change the board. 

The advice from @57Deluxe is correct in terms of that resets any stored state PM data on the board and resets soft fuse protection like a USB short from the 5V to ground. So remove the battery, remove the charger if connected and hold power button down as described before anything else 

As someone who has been repairing laptops for 20 years here's the basic order of events in terms or evaluating a non booting laptop ONCE you know things like power is getting past the DC socket etc ... (Fans spinning, power light on  \ charge light on etc )

When you turn it on the machine attempts to POST (power on self test) ..... during this sequence it looks for the ram and the video card etc and if it doesn't find something it will alert you with beep codes .... now the beep codes can very between manufactures of BIOS  so you look for the error code list for your model  ......  At this point you don't even need ram in the machine or a harddrive connected .... if no beeps even then it needs a board

If you do get beeps with no ram but nothing with ram then remove both SODIMM''s and try one at a time in one slot then the next .... very common for one ram slot to go faulty, especially if it's a stacked double ram slot arrangement as one row of pins tends to be thru hole and one set of pins tends to be SM with more leverage on the joints due to the higher slot. Chances are at least one slot and one SODIMM will not be faulty and machine should then post

Processors in my experience do go faulty (especially AMD mobile processors ) but they don't tend to go intermittent .... generally they go dead and stay dead ..... on a lot of boards now the processor is soldered to the board so a failure in that case means a new board. 

If you do get it posting then on a lot of Dell's you can hit F12 to start the onboard diagnostics  ... this is contained in EEPROM so independent of windows, harddrive or any software issues .... the onboard diags can pick up and report various failures like fan \ interrupt timers and corrupt ram 

Unfortunately  by far the biggest cause of laptop motherboard failure is due to BGA joint failure or substrate failure of BGA chips ...... basically rather than having little legs all around the chip like the old days the chip has solder joints on the bottom ... little balls (BGA means Ball Grid Array) and to solder the chip you basically get it hot enough to melt the solder in the ball grid joints during manufacture of the motherboard. Now laptop boards get hot in use (especially AMD based laptops ) and this heat and the flexing of the board can lead to failure of the BGA joints. Now you can technically reheat the chip to repair this problem but in my experience it's never 100% reliable for very long ... to the point I don't do it any more. Always be careful when buying a board that it's not a previously failed BGA board that's been re-worked ... tell tale signs will be red, blue or black gunk around the outside of the chip to stop it moving while being reheated. Such a reworked board is unlikely to be reliable for long 

If by blank screen you meant it does post but fails to boot into Windows then you can ignore all the above stuff