Sudden opengl Error

I've been playing Cosmic Break for little less than a year now. My computer's a little old and slow, but the only problems I had to deal with were lag (which although happened frequently, didn't cause too much trouble with gameplay). I kept everything like graphics on the lowest possible settings. Memory in options I kept under "M" and didn't have "Thread Optimization". I don't if it means anything, but I switched memory capacity to "L" and went with "Thread Optimization".
Next day, started up Cosmic Break, black screen, exits out and suddenly I'm getting some report saying

Fatal Error
OpenGL Hardware Acceleration is invalid.
Please check your display drivers.

I've been looking around, but people with this problem mostly have it when they first get Cosmic Break. I've been playing for awhile and this never happened.

I'm far from a computer expert. I don't know if changing the memory capacity really did have something to do with this or not. Either way, I don't know what's going on or what I should do...can anyone help?

My first guess would be that you do not have enough memory to use the L setting. Go back to M or S.

To do that, though, you will have to go to C:\CyberStep\CosmicBreak_eng\programs and delete your option2.ser file. When you start the game again, it will reset some of your options back to their default settings, namely the memory size option. If you try to run this game with a larger memory setting than your system can handle, it will just endlessly crash until you do this.

won't starting with the Safe mode would be just the same?