HELP! Keep getting "No Sync" Signal on Wacom Cintiq 12wx

I bought a VGA adapter for my Cintiq so I could use a better resolution for it. Everything worked until my Macbook Pro asked me to install some upgrades, and then after that, it just wouldn't work and I kept getting a "No Sync" error message. Did I do something wrong? Like seriously, no matter what, this thing keeps giving me some sort of error signal. First it was "Signal out of range" and I tried to fix that, and now it won't turn on. I'm starting to pull my hair out. I really, really really am begging all of you, to please help me. I've turned the computer on, off, unplugged everything and then replugged it. I've switched from DVI to VGA. I'm going totally mad, I need your help. I have an ungodly amount of work and I just bought this thing. Wacom's closed for the whole weekend till Monday due to the Holidays. PLEASE help me, PLEASE.