Unexpected exception Access Violation error

Hi,
Today I experienced an unpleasant error and I stuck with it. No idea why and how can this be solved. I have no idea what is causing it since yesterday all worked just fine. Is anyone there that might have a solution for my error? Can’t this error be prevented in the future?
Thank you!

Unexpected exception
Access Violation
File – C:Windowssystem32KERNEL32.dll
Offset – 0x0004d0b7 Line 740
