Excel 2007 : Problem with Time

[AlanWade]

In my spreadsheet I have columns 'd' and 'e' formated as time and 'f' to make the basic subtraction. The problem I am having is that whereas the input in d and e should be in hrs:min, if I enter just 1 instead of 07:01 it gives the data as
1900-01-01 00:00:00. I have tried with Validate but all I can get that to do is throw up an error if letters are typed. I have attached my workbook as an example, if you look at June or July you will see what I am trying to say. I am using Excel 2007.
Any help will be appreciated.

Regards
Alan

[NBVC]

You can try:

Data|Validation >> pick Time from Allow menu

Enter Start Time: 00:00

End Time: 23:59

[AlanWade]

Thanks very much that worked! You make it sound so easy.
Regards
Alan