This used to be true, but Windows 7 is a pretty solidly secure OS. 

Every major Internet provider I'm aware of has switched to modem/routers, so fewer and fewer of users are directly connected to the Internet, which closes the door on virtually all threats outside those initiated by the user themselves.  Stay away from phishing attempts, don't download exes from untrusted sources, and leave the Windows update service on auto. 

/ 25 years using/developing on Dos/Windows
/ No infections - virus, trojan horse, or worm
/ No "hacked" accounts, stolen USD or BTC, etc
/ Did lose some family photos once due to a flawed backup strategy. >_<