yes, check both monitor and VGA card ports: make sure there are no pins missing (they've been know to "just pull out". and get a chart - some pins are supposed to be missing). make sure your plugging it in all the way seated.
CRT have "color drive", if you loose RG all you have left is blue. There's an outside chance you have a loose power transistor on the backboard of the neck and can re-solder it, or that you can adjust the RG to increase them (say, maybe you move around the adjustments and they start working). There's at least 1/2 a chance the RG are blown. Anyway: 10,000 volts. Don't do it unless you grew up keeping yourself alive without others helping you to stay alive (ie, the 1980's v. the 2000's). It will end your life early if you don't know what your doing. And you would likely not even feel it has done so, you'd just die younger.
be totally serious or don't attempt it. it's way more time and money, in today's dollars, than it's worth to "begin learning to do" for an old monitor, believe me.