Extreme I have a tip for u:
assuming the fact we r talking about ur home puter.
assumingthe fact that you don't run any server.

So there is one thing u can to get rid of: TCP scans
use a firewall set up to drop any connetion request from the outside (exception can been done for P2P) in TCP term refuse any SYN from outbound.
For those who don't understand, a client is always at connection initiative & then by doing this u will forbid any server or scan (tcp based) of any kind to connect u.
This can be enhanced with rules for the inbound, like restriting to the services u only use (21: ftp, 80:http, yahoo game: you decide, .....)