My hp vf15 monitor flickers on and off when it is plugged

what PC, what monitor , both HP.?
windows 8.1 sure.
if the monitor flickers plugged in other PC , the monitor is bad.
first lets do that, to cut the job in 1/2..
see?
both the monitor and PC have service tags (HP)
and states a full model.
like HP 8000 deskp
and HP 1703 monitor (old 2004)
there are 1000's of models, 1984 to now.

First of all, before you look which one to buy, you need to find out which Video Port does you Mac has, i.e. VGA or DVI or Mini DVI or HDMI. Once it's confirmed, you have to find out the same with your monitor, so that you can buy the appropriate cable.

Pictures Below:
1. VGA


2. DVI


3. Mini DVI


4. HDMI


Good Luck.
Thanks for using FixYa.

The monitor itself most likely needs a screen replacement. These are usually very costly, and you will probably find it to be more convenient and less expensive to simply purchase a new monitor.

u can fix by replacing new switch or u can give direct connection

Need to change or repair monitor at this stage.

sounds like the cable is out but i dont know how to fix it srry

Try www.hp.com partsurfer

Your LCD screen needs to be changed

why not use a known good monitor
in 1 minute flat the truth.
not only that you can move or bad monitor to another pc
and see if it works.
also the cable can be bad.

Replace 4 dead 470uf 16v capacitors and 1 1000uf 16v capacitor on power in circuit board. worked for me.