pinging a numeric address works but not an URL (alphameric)

After uninstalling ZoneAlarm (version 6.5), I could no longer access the web.
Suspecting a problem with the TCP/IP connectoins, I have noticed the
followings:

- pinging an IP numeric address in the local network or in another network
works fine (although I got 2 spurious characters between "Pinging" and the IP
address when replying - Thus I got "Pinging yö 130.104.xxx.yyy" where yö are
the spurious characters [not seen in another compouter])

- pinging an URL (alphameric address) does not work anymore (thus a "ping
www.mysite.com" which would normally work gives "Ping request could not find
host www.mysite.com... (the address is resolved from another computer)". I
checked that the DNS server replies to ping and is, therefore accessible;
other computers using the same DNS server work fine)

- tracert (to a numeric or an alphameric address) does not work: only one
hop and then "no resources"

I ran "sfc /scannow" to replace any corrupted Widows file (it ran to
completion; I was asked several times to insert the WinXP CD Rom and suppose,
thereby, that some files were indeed replaced), but to no avail.

Any suggestion (apart from reinstalling Windows entirely ...).

Can this be corrected using the Microsoft repair console (and avoiding
having to reinstall Windows entirely ...) ?