https://grc.com/x/ne.dll?bh0bkyd2
Take the test in the above link to find out.
In today's world, every computer is connected to the internet. Computer is basically "useless" without it. Most of us have a high-speed connection which means we have a static IP. Many of us even leave the computer on 24/7 which means the computer is in threat of being hacked by "NORMAL" computer end users.
So who is "safe?" Take the test and you will find out.
If your computer failed the test, I suggest you to get a software firewall (eg BlackICE) or hardware firewall (eg router). WinXP's own firewall also worked fine.
Also, PLEASE set a password for the computer. Don't turn on the GUEST account. If not, the computer is EASILY accessed by a simple "MAP NETWORK DRIVE" in Windows Explorer.