The issue is the time component doesn't align with Date().
The thing to understand about dates, is that they are stored as integers and time is a fractional component of one day.
So try this:
Code:
SELECT WOTracking.Employee, Count(WOTracking.OrderNo) AS CountOfOrderNo, WOTracking.ContractCo
FROM WOTracking
WHERE (((WOTracking.Date_Time)>=Date() And (WOTracking.Date_Time)<Date()+1))
GROUP BY WOTracking.Employee, WOTracking.ContractCo;
EDIT: Once again, too slow in my testing and typing, and Paul beat me to the punch!