These is software that you can use to see if he is really blocking you or just happens to be offline.
MSN block Checker
MSN block checker 2
#2. The Alien Passport Technique
No shocker, this do-it-yourself one, as most of you will already have thought about this before, but here we go:
1) Create a new Hotmail Passport with a user name that has no relation to you whatsoever (tip: use a foreign name from the other gender).
2) Download a polygamy patch for your version of MSN Messenger.
3) Start a second MSN Messenger client after applying the patch and log-in using your fresh and clean MSN Passport.
4) Choose "Send an instant message" from the Actions (or Extra) menu and instead of selecting somebody from your Contact List (which should be blank with your new account), fill in the email address of the person you suspect of blocking you.
5) Send him a message like: "Hi, are you the person who mailed me earlier about my site?" or something completely else (whatever might get him/her to react).
6) If this person replies while being offline on your other account... somebody doesn't really like you
NOTE: This technique fails when the suspected blocker has chosen the default privacy setting to "Block All Others" (= users not added to the contact list).
#3 The IP-Scan Method
Contributed by inspiron2002
1) Find the IP of the suspected blocker
2) Scan the IP for the MSN PORT (1963)
3) If there's none, the person is disconnected from the Internet.