Unable to connect to server!

I have been using SmartFTP for over a year and it has been a wonderful program to me to edit my website. However, since about a week ago, I have been unable to connect to my server. I get errors like the server is timing out, and that the machine is 'actively refusing' me. I dont have a firewall, and I dont have any privacy things installed onto my computer. My hostess and I talked about it earlier this evening, and she is able to log into my account, and I was (of course) unable to, both with SmartFTP and a program she had me try, called WS_FTP. We deduced that it is in fact a problem with my compter. Any help is most appreciated!
I have windows XP, and have tried almost everything I can think of. Are there any suggestions?
Thanks in advance
Jennifer

just try to remeber what changed since it last worked, e.g. have you installed sp2 for winxp? also, please always post the connection log when reporting problems like this.