TSGL: LCD monitor turns black

[gcc]

Hi all.  For the past month or so my LCD monitor has been periodically 
losing its picture and going "black-screen" on me.  When I push the 
monitor-button the picture comes back on, lasting anywhere from 5 to 20 
minutes before going blank (black) again.  I bought the LCD about 5 years 
ago and have been using it anywhere from 3-7 hours a day.  Is it time to buy 
another monitor?  Gosh my old CRT monitor, given to me by my brother-in-law, 
lasted 10 years between the two of us. I finally chucked it out for new 
technology, (but it was still working!)  Is there something I should 
check-out before I look for another screen?

Thanks
Glenn