What do you mean by basic or classic mode?  Are you talking about Win7 OS modes, or video modes on your EVGA video card?
In any case, have you tried a different Monitor?  If the problem goes away, your existing monitor is probably defective and must be replaced.  If the problem persists, it could be due to driver problems such as instability or corruption.  At this point, you should attempt to uninstall your current video driver and reinstall with the latest driver available on EVGA website.  If that doesn't work, you could try the driver rollback option (which you can google) if available.  Many video cards disable this feature on initial installation.
Before you attempt any software repairs such as driver repair, we recommend that...