Monitor wont turn on, light flashing

A number of things can cause this. Incorrect BIOS settings, cable problems, a faulty monitor or problems with your video card.

1) If you can change the monitor cable - do so
If it worked, great else - carry on....
2) If you have two monitor inputs on your computer swap the connection to another input, only if it is on another card. If it worked great, else carry on.....
3) Try a different monitor to see if the same thing occurrs... if it does then it is either video card or BIOS
4) Reboot your computer and watch the screen - it will tell you to pres a key to enter BIOS or setup - do so.
Switch of cacheing of Video RAM
and Disable ACPI settings - all power and green energy settings. If that does not do the trick then it is most likely your video card - or your monitor... borrow a monitor and video card for ten minutes and you will find out which is the problem