I finally entered the world of Windows 7, albeit only because my laptop died. 
 I am a historan who needs to calculate dates into the 18th century.  Xdate 
always worked just fine in Excel 2003, but when I load it into the new 
computer, Windows 7 sees it as an old process and refuses to recognize it.  I 
need those date calculations, and I'm not thrilled with buying a later 
version of Office - if it even is in the newer versions - because A) I don't 
otherwise need it, and B) I've seen the recent version of Office and want no 
part of it.

I bet you were using an addin by John Walkenbach:
http://j-walk.com/ss/excel/files/xdate.htm



Help with scheduling issue wrote:
> 
> I finally entered the world of Windows 7, albeit only because my laptop died.
>  I am a historan who needs to calculate dates into the 18th century.  Xdate
> always worked just fine in Excel 2003, but when I load it into the new
> computer, Windows 7 sees it as an old process and refuses to recognize it.  I
> need those date calculations, and I'm not thrilled with buying a later
> version of Office - if it even is in the newer versions - because A) I don't
> otherwise need it, and B) I've seen the recent version of Office and want no
> part of it.

-- 

Dave Peterson

"Help with scheduling issue" <Helpwithschedulingissue@discussions.microsoft.com> wrote in message 
news:28A5F613-E540-4DAF-B27B-7FA082838DA2@microsoft.com...
>I finally entered the world of Windows 7, albeit only because my laptop died.
> I am a historan who needs to calculate dates into the 18th century.  Xdate
> always worked just fine in Excel 2003, but when I load it into the new
> computer, Windows 7 sees it as an old process and refuses to recognize it.  I
> need those date calculations, and I'm not thrilled with buying a later
> version of Office - if it even is in the newer versions - because A) I don't
> otherwise need it, and B) I've seen the recent version of Office and want no
> part of it.

Remember also the 400 year trick.
400 gregorian years is a whole number of weeks,
so everything except easter repeats every 400 years.
To get the weekday for 1/1/1800 look at 1/1/2200 for example.

Hans T.