Monitor randomly goes blank?

my monitor occasionally goes blank (like black and the backlight even turns off), and then comes back after a few seconds. it doesn't seem to do this during any specific program or situation, it happens constantly at random intervals. Yesterday, my monitor actually went blank and then said that it couldnt display this resolution, and then was fine after i switched from auto detect to digital (i'm using DVI). to further complicate the situation, i have zero problems when using the VGA input on the monitor. the problem also occurs when connected to other computers, so i'm also going to rule out the video card. oddly, this problem stopped for many months after having initially happened when i got the monitor in january. all i can think of is that the monitor is defective, which is less likely because the vga input works flawlessly. so my main thought is that maybe the dvi cable is damaged. yeah yeah, you're gonna say why not just buy a new one? well i'd rather get a second opinion before i go and spend money on something that may not even help. by the way, my monitor is a Dell SP2008WFP.