I have a Viewsonic E90f monitor, 3 years old, that has had intermittent problems for the last three months where it would have lack of brightness or it would go blank. This happened on and off for a while, now it seems to have gone completely dead. I have a second identical monitor that is having the same problems but is still working (for now). Any suggestions on what could be causing this? Would it be easily fixable? Thanks for any help, Fred