ok, first of all what you asked is not possible without each computer having internet access.
first way is to create a database in a central computer, check the initialization count and update a table each time the program runs. this is the easiest and most convenient way.
another way is to put the power of cloud to use. create a microsoft skydrive account. create a file there that stores how many times the program had run. on initialization of your program, download that file using skydrive .net api link
, update it, and upload it. do not forget to encrypt the file contents to prevent tampering with it.
if you do not have any means to operate a central server or skydrive, as an alternate way, you can use google docs. this is a long way and not optimized in any means, but its what comes to my mind now. using google docs api, store how many times the application had run in a spreadsheet.
as a funny way, create a twitter account and tweet zero. on opening the program, read the final tweet and retweet the update using twitter api.
I'd stick with skydrive though