I am using asp.net with c#.
My issue is this that I am setting cookies to check that the same user is returning or not but user are returing from the same machine with different browser. Is their any alternate I would know that same machine user had visited my site.
Not unless you checked their IP, but then again that's probably worse since multiple computers are usually hiding behind 1 IP.
The short answer is - NO !!!
If there was a way to track the same user no matter what s/he is using, than browser vendors and protocol specification would be doing an awful job in protecting our privacy :))