Moniter suddenly blacking out

[ayushman9]

My Widescreen TFT ( LG L194WT ,connected via DVI cable ) is giving me quite a lot of problems but i am unable to guess whether it is monitor.or graphics card or any other device fault

Sometime when i boot after passing the windows vista boot screen the signal to monitor suddenlt gets off ,ie blackout and monitor says "no signal or digital power saving mode " . At the same time when i push my on-off key in PC ( i have mapped the on-off key to shut down ) ,the pc does not shut down and i even can't know what is happening . I have to hard shut down . This problem goes for next subsequent boots . I have to then switch off the pc for about 5 hoours or so after that the problem automatically dissappears but then return in 3 to 4 days.

The problem is now days it even occurs when i am using pc inside windows . Say i am surfing a site suddenlt blackout ,and the pc won't shut down through acpi power button or alt +f4 --f4--f4 . I have to forcefully shutdown .

What could be the problem ?

[comp@ddict]

which monitor? At least mention that!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!