We are developing a paid website. Obvious task is to be able to stop users from sharingthe user ID and password combination amounst their circle so that only one person needs to pay.
Now I know monitoring IP is almost useless. Getting MAC Id is also browser specific and so on. So these tools are not foolproof.
I am looking for a utility/programme that can be installed on user's computer at the time of registration albeit by informing...

We are deveopingawebis te in asp.net. There are tempelates of each aspx page made in the form of excel sheet. Upon completion of the online calculation, the user is to be allowed to export the results to excel and save them. There would be obviously no formulae in such sheet
I do not want to install Excel on theserver and instead want to utilize the Excel installed on the user's computer for this purpose as every user's computer is expected...