Sorry I did not respond earlier, but I did not see an earlier response.
Works, as far as I know, is put on the system by some sellers as a replacement for Office. I would have to guess that the calendar itself is not causing a problem, but if there is something trying to use it or an install glitch occurred, I suppose it might be involved.
Since it is not a part of Windows 7, you should be able to delete it, but you might first check to see if there might be something trying to access the calendar causing the problem.
Checking the event viewer might help you track down a problem with the software by showing a pattern of error messages or warnings.