The place that i am at has internet but you have to have a internet browser to set it up so i cant connect my 3DS. I have a router and and have gone to the settings and enabled Internet connection sharing but when i try to connect it
it connects to the router then cant connect to the internet
I am sure i entered the security key correctly and i have DHCP enabled
does any one know what the problem is ?

Internet connection sharing has nothing to do with the 3DS. Try taking all security off of your router (WEP or WPA). Then try connecting... If it connects and you can battle other people on the internet, then there is a problem with your security settings.

I tried turning security off and it didn't work
sorry if i didn't explain correctly what i am trying to do i was in a hurry
i am trying to use my computer as a bridge like this:
Internet connection>Computer>Router>3DS
i looked online and it said that internet connection sharing would do that. Will that work?Is there something i am doing wrong with that?

No, thats not going to work, unless your computer can Broadcast the wireless signal. Usually, internet sharing on PCs is done thru the Ethernet port, which obviously will not work with the 3DS.

You shouldnt NEED to use the computer as a bridge. The 3DS should be able to connect to your router itself.

in my original post i noted that the router at the place i am staying at wont let you connect to the internet unless you have a internet browser witch the 3DS dosen't have yet. so i connected my own router to the Ethernet port and tried to use internet connection sharing
witch is not working and i was asking for help using that.

Added after 48 minutes:

Okay i figured it out i had internet connection sharing set up on the wrong connection

will connecting to the internet be easy as I found it really hard to connect with my DSi