HP vs17x flat screen monitor won't come on, blue light flashes.

Check for back lighting. The screen will glow.
Sound like the power board is out.

It can be 12vdc power supply section with bad cap, that will be the first place to look, or it is the backight inverter circuits, worst case will be the lamp assemblies, but find out first if the caps are good or bad, please note that bad cap may look normal but can have high ESR.
If you are going to DIY and have proper tools and know safety precaution then please read on:
Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply (they should be replaced in a set), blown fuses; poor solder joints, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed monitors to get some ideas what to look for: http://s807.photobucket.com/home/budm/allalbums
Post back what you see inside so we can guide you further and it will help out other people in the future also.

http://en.wikipedia.org/wiki/Capacitor_plague
Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.
Please post back what you find.

you have three bad capacitors on the monitor motherboard

Needs to got to monitor repairer.

Disconnect monitor cable from back of the computer and see if u have a error msg on the screen > if u find a error msg like " NO VIDEO SIGNAL"> then ur monitor is fine or else ur monitor is BAD

Sounds like a power surge fried the electrical connections inside.

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Good luck

Let me know if this is helpful for U

Have you tried connecting this monitor to another computer, even a laptop. This would tell you whether the display is bad or the video card is the culprit. I suspect the monitor's power supply is dying. Taking it to a pro for repair should cost @55.00. Buying a new monitor @ $100 - $125.

This is most likely the power inverter board in the monitor - this is common in many monitors. If it started taking longer and longer to display an image, and the power light is blinking on-and-off, that's the problem. You can confirm that it's the monitor and not your computer or the cable by plugging in another monitor if you have one to try.

If it's under warranty, send it back, if not, there are inverter boards for many common models of LCD monitors that are replaceable. The board can run anywhere from $50 on up. Depending on how old it is, you may find it better to just replace it with a gently used one from ebay.

Your main board is having a problem.