A family of Microsoft relational database management systems designed for ease of use.
See http://www.techyv.com/questions/program-quits-unhandled-error-occurred-access-violation
However, if this is a new problem and the system worked OK previously, I would suggest using Windows System Restore to restore the system to a restore point before the problem occurred.
If it occurs when you first switch on the system, I would try using your Windows Installation disk to try repairing Windows.