why not test the monitor on another PC to prove which box is bad
the mon or Pc.
NO OS stated. be nice to know which of 20 OS it is. Windows something is my wild guess. but there are so many, now.
the monitor will always tell you no sig ,
one PC first. this gets the VGA chip alive first. with all sigs
then turn on the Monitor ,if those sigs are missing the monitor always tells you they are, and will not lie to you.
that monitor is newer. not relic, and new monitors never do self sleep like in year 2002. there is no internal sleep on your monitor
it only sleeps on DEMAND, from PC VGA card (lets to VGA ok>?)
simple is easier to troubleshoot.
the 2 sync lines do the sleep mode per VESA spec.
I bet the monitor tests prefectly on any other PC.
so lets go from that fact, and work the PC end. make sense?
ok so the VGA chip is BAD.
right, but what can make it bad even when not BAD really.
answer lots, but wait , ive no idea at all what you have.
p7-1148 PC is a desktop
and many desktops , vast, have 2 video chips
one on the MOBO and one in the PCI slot.
i cant see your Desktop rear so must go wild guessing now.
the first thing i do with any older PC is clean all that lint out.
after all if the VGA chip overheats or CPU they shut down.
all do. every one. made does that overheated.
HP has full support page on this nice PC. Decktops are my joy.
im reading your product spec, now. online at hp
it tells me this PC comes with many options video cards etc.
so Ill not guess now. that. (I open the case and look is what I do)
it has option HDMI card there, ? does yours?>
here is your graphic page
Integrated video is not available if a graphics card is installed.
- Radeon HD 6370D, 6410D, 6530D or 6550D Graphics (model dependent based on processor)
- Supports PCI Express x16 graphics cards
- Two DVI-D ports (Both ports can be used at the same time)
the above means, that you are using ON BOARD VGA or
the VGA Card.
which is it , the one you use is failing.
if a card remove it and use the OTHER VGA JACK (onboard)
so open the case per online manual.
see 2 fans, make them clean,
make heat sinks lint free.
now that it has Fresh air we see if the PSU works.
if the PSU is ok,
diagnosis is serial process, i check the coin cell on each i touch.
after lint removed. 2.9vdc min, new is 3.3vdc.
then i gander at that PCI video card, is the aux power jack fell off?
black yellow wire set, if present , all fast cards have that.
then the video card GPU chip see that, see if the heat sink on it is clean? and i fitted with a fan does said fan work?
beyond that , is more test, ill stop here, most here fear opening case.
see upgrading guide here, for access to pc,