How do you open a hp model a6750f prod fq563aa-aba so I can see if I can fix it.

progress, fans blow.
does cd tray eject?
does the caps lock toggle on demand, the LED go on then off with caps lock pressed over and over.

beep codes those are very important
each has meaning, count them can you
or caps falshes by self same errors as beeps.
the errors are
bad power
bad memory
bad video card.

do you have 2 vga or DVI video jacks on gear of PC? 1 each?
is there a video card in the PCI slots

my guess if you tested your monitor on a good PC it would work ok ending worry on it is minutes work.

the PC has many failures to get NO SIG>
1: bad PSU, it seems to work though.
2: bad memory run 1 stick at a time to prove it in bank 0 (means lowest numbered bank)
3: bad video card, if there is one there.
or if it is there and its fan is dead bingo.
4: does the CPU fan spin? you heard them
but do all fans spin? seen and heard,
they MUST.

even a bad vGA cable but testing the monitor on aother PC with that cable proves both are ok, mon and cable. progress, fans blow. does cd tray eject? does the caps lock toggle on demand, the LED go on then off with caps lock pressed over and over. beep codes those are very important each has meaning, count them can you or caps falshes by self same errors as beeps. the errors are bad power bad memory bad video card. do you have 2 vga or DVI video jacks on gear of PC? 1 each? is there a video card in the PCI slots my guess if you tested your monitor on a good PC it would work ok ending worry on it is minutes work. the PC has many failures to get NO SIG> 1: bad PSU, it seems to work though. 2: bad memory run 1 stick at a time to prove it in bank 0 (means lowest numbered bank) 3: bad video card, if there is one there. or if it is there and its fan is dead bingo. 4: does the CPU fan spin? you heard them but do all fans spin? seen and heard, they MUST. even a bad vGA cable but testing the monitor on aother PC with that cable proves both are ok, mon and cable.

so the PC seems to have full power !
5vdc is there. 12vdc is fan power. vga cards too.
no text on the screen ever.! right?
my guess is bad screen or bad vGA card.

try to know , i cant see the back of your
desktop case.
so can't tell what is there, (called options)
you have not told the monitors make or model yet, why,
why not test the monitor on any other PC? first, if a monitor is 100% dead.
that is always step one.

10000 of monitors made, which one do you have. for over 20 years,
know this, ? below... history and tech.
monitors before year 2010 are all CCLF
almost all are dead now. CCFL back lamps.

if used, daily they all died long ago.
or near, now;
on avg,. most died year 2015.
(the flash light trick proves it)

if the monitors OSD screen (on your demand)
is dead, so be the monitor. How test?

monitor 101
power on just the monitor
see if you get HP (if its HP monitor) get HP logo, now,. or text or scanning or /?
or "NO SYNC, no signal, out of range" errors
then immediately push the monitors menu button , be quick say under 5 seconds...
see OSD? graphic box, on screen display?
repeat that 10 times, fast, if monitor is dead it is.

or just test the monitor on any PC (VGA port)


why not post what you own in details
gee even a photo of monitor and PC rear .

works. so the PC seems to have full power ! 5vdc is there. 12vdc is fan power. vga cards too. no text on the screen ever.! right? my guess is bad screen or bad vGA card. try to know , i cant see the back of your desktop case. so can't tell what is there, (called options) you have not told the monitors make or model yet, why, why not test the monitor on any other PC? first, if a monitor is 100% dead. that is always step one. 10000 of monitors made, which one do you have. for over 20 years, know this, ? below... history and tech. monitors before year 2010 are all CCLF almost all are dead now. CCFL back lamps. if used, daily they all died long ago. or near, now; on avg,. most died year 2015. (the flash light trick proves it) if the monitors OSD screen (on your demand) is dead, so be the monitor. How test? monitor 101 power on just the monitor see if you get HP (if its HP monitor) get HP logo, now,. or text or scanning or /? or "NO SYNC, no signal, out of range" errors then immediately push the monitors menu button , be quick say under 5 seconds... see OSD? graphic box, on screen display? repeat that 10 times, fast, if monitor is dead it is. or just test the monitor on any PC (VGA port) why not post what you own in details gee even a photo of monitor and PC rear . works.