That might depend on your email-program (Windows Mail?), but I don't think so. The thing to do, probably, a clean install of Windows Vista. That should get rid of that virus.

Or maybe you can. Usually, the password to access the mail-account at your ISP is stored in the account properties in your mail program. And probably you checked the 'remember password' box. Now clear that password and uncheck that box. See that you can't send any more yourself without typing in the password to connect. Probably that virus can't connect now.

But I wouldn't want to have such a nasty virus on my PC. So I would go for the clean install even if it works.