Ping goes, sites do not open, what's the problem?

Question

Browsers

Given: Windows Server 2003 x64, cisco switch, cisco router, adsl modem, came in the morning open firefox does not open anything freezes, internet explorer also does not write anything "it is not possible to display the server" - it also does not write dully nothing happens white everything when this internal network pings perfectly, sites also ping, I wanted to install opera, so when installing, the download in the interface also does not work, although a separate mail server is running a system manager near me (fribsd) letters come in, the Internet on other PCs is there a joke? maybe the protocol is hanging, I understand something at the application level ??
UPD: The host file, and I checked the path to it, the ftp connection is on, the Internet is opening for other users,

Answer 1

=) Are you pinging by host or by IP? if the host and pings run, then the problem is in http, if there are no pings on the host but only on the IP address, then dns does not plow on the machine.

Answer 2

What is the problem - HZ.
Standard action - modem and Tsiski off-on, restart the server. Did?

Answer 3

check ports. may be closed