Hi, I found that Excell displays wrong "day of the week" for 01-01-1900 (as Sunday) , where as the 01-01-1900 is factually a Monday (Use Windows OS Calendar and verify).
This seem to be arrising from the fact that Excell is presuming that 1900 is a Leap year, where as 1900 is NOT a leap year (due to its non devisibility by 400). Therefore, all dates upto 29th Feb 1900 are displaying the wrong "day of the week".
Create a excel sheet with dates from 01-01-1900 and expand upto 01-03-1900 and find its correspoding "day(s) of the week".
Compare the correct "day of the week" by clicking on the OS calendar at the right bottom of your Windows screen.
Have fun guys.
Dr.M. Ramasubbu