Since they are independant progams on your pc, I doubt Win XP is making you login. You can check the firewall status of Win Xp and see if it's up, but again, I don't think that is your issue.
Which ftp client do you use? I use ws_ftp and I have to login to my server everytime I access the program. I still think that Email issue can be resolved by the last post to Microsoft's knowledge base.
As far as your ftp, that shouldn't be affected by anything than a firewall, and even at that, it should only prompt to you to allow access.