Problems with Outlook Express

For years now I have been using the Outlook Express as my sole e-mailer with no problems at all.
From December 24, 2003 and on can still receive and open the e-mails but I can send none and the only message that pops up after every try, is the following:
“The connection to the server has failed. Account: ‘pop3.netonline.gr’, Server: ‘mail.netonline.gr’, Protocol: SMTP, Port: 25, Secure(SSL): No, Socket Error: 10060, Error Number: 0x800CCC0E”.
No change has been made to the H/W and/or S/W, no windows update — at least for the last 40 days, and no ghange to any parametres of the MS Office programs (MSO xp Pro).
The PC is a 2.4MHz Pentium IV with 1Mb ram on a Gigabyte 8IPE-1000 Pro M/B and the S/W platform is Win xp Home.

My heartiest wishes to all
Constantine Papanikolaou
Thessaloniki, Greece