When you start-up your computer, try wating 3-5min, I find that it helps.
If Windows is your only firewall then you can tell it to update it when you want. Go to START, CONTROL PANEL, WINDOWS UPDATES. Then tell it when to update when your want, like Bi-weekly @ 5:00, or whatever. If its not there then Go to Windows Security Center. Or Windows Firewall and allow the Limewire program.