That model is approximately 10+ years old, which isn't bad for a budget-priced monitor, so it may simply have packed up and needs replacing. It may simply be the backlight that's failed on it, but buying a new backlight for budget priced10 year old monitor just doesn't make economic sense, that's even assuming you could get parts for it now.
Just buy a new one, and take the opportunity to get one with larger screen as a 15-inch 4:3 one is inadequate in my view these days.
However, you may want to connect it to different PC or laptop first, just to be quite sure it has died.