is there a way to tell?

[Boo Boo]

what day the windows os was installed on a computer?

 

[Farang]

Yep, it is all here

 

[aircooled]

http://windowsxp.mvps.org/getosdate.htm

 

[xavier es]

SIW, systems info for windows. sorry I dont have a link.

I think belarc also displays the date/time the os was installed.

 

[MadAmos]

Systeminfo.exe at the command prompt for me 8/28/2006, 5:30:33 pm