Assumptions on my part since MSN works: Your DHCP, default gateway and possibly static IP are verified as OK. Also assumed is that you didnt install himachi.
1. Virus scan and spyware scan your system.
2. Try flushing your DNS cache (I doubt this will work)
http://www.tech-faq.com/flush-dns.shtml
3. Try changing your DNS settings to opendns.
I honestly have no idea how well it would work if you are not US based. (I'm assuming your either in France or Canada)
Here is the link: (I would set it up on the computer and not the router for testing purposes.
https://www.opendns.com/start/
If that does work and it seems slow, then get the DNS server settings from your ISP (usually on their configuration page) and manually put those in.
4. Winsock XP fix
Follow the instructions here:
http://www.snapfiles.com/get/winsockxpfix.html
5. Possible bug with XP service pack 3 (i dontk now if you are running vista or XP)
http://www.microsoft.com/downloads/details.aspx?FamilyId=6ADAF000-E2AA-4EAF-81F4-6AF385768280&displaylang=en
6. What virus software are you using? I've heard of older versions of Norton screwing things up. Google a norton removal utility to strip it out.
7. let us know if you get it working and which one worked! If you don't get it working then there is a few more things to try before reformatting. (ie. posting your network settings, getting a hiJack this report etc.)