Weirdest problem?

[doiexist]

I work on a lan and we have DSL internet connectivity.(IE)All pcs except mine have access to internet.Their is no problem with physical connectivity as i can access other pcs on lan And all the settings like TCP/ip ip add, gateway are correct.I can even ping the gateway(router).I have even reinstalled the os i.e, win98 but no use.Recently somebody told me that it could be problem with registry(i think windows dosnt overwrite the registry during reinstall).He evn told me that the acces can be blocked to internet by makink some changes in registry for IE.What and where r these settings?Can i just overwrite the registry settings of internet explorer with the other pcs ie. Any sort of help will be highly appreciated(links,suggestions) as i am totally frustrated wiyh this problem!!!

[RVerminck]

Are the PC's connected to the LAN created in a workgroup or in a domain. Because the number of PC's are limited when joining a workgoup with the same workgoupname. You can ping other IP-adresses buth the PC is running as a complete stand-alone.

[doiexist]

Pcs r connected as domain, besides that i dont have problem in communicating with other pc on LAN i.e i can share read other pcs and can see them in network neighbourhood. The only problem is i cant conect to internet.