Again, this will reduce your chances of being scanned, but it will not eliminate it completely. After the hacker finds your computer on the network, he needs to find an open 'port' on the computer. Every service running on a computer needs to talk via one of these ports. There are a great many ports, and most of them are not used at all. So, not all ports have good uses.
Port scanning is a fact of life on the Internet.
I run some fairly sophisticated monitoring software on my system, and it shows me an average of 10 attempts per day to access my system. Since you can't keep the hackers from finding your IP address, you need to make sure that you don't have any open ports on your system for the hacker to exploit. You can get a quick idea by visiting one of the 'scan me' sites on the Web. They also have a lot of good information on protecting your system. Some ports can be closed by simply choosing the right options when configuring your system.