Help! my computers are under attack.

I have been having troubles with google search for a few months. It always redirects me to unrelated commercial websites, so I have been clicking Cached to go to the websites I want.

Yesterday, two of my computers showed the same information when I click Cached as below. Can someone tell me what's going on. The following IP address is not my own computer. I am using the wireless without password. Am I under attack? Why both computer showed the attach by the same IP? Is that an Mac or PC? Where that computer located? Can that computer attack me by proxy system?

Our systems have detected unusual traffic from your computer network. Please try your request again later. Why did this happen?

This page appears when Google automatically detects requests coming from your computer network which appear to be in violation of the Terms of Service. The block will expire shortly after those requests stop.

This traffic may have been sent by malicious software, a browser plug-in, or a script that sends automated requests. If you share your network connection, ask your administrator for help — a different computer using the same IP address may be responsible. Learn more

Sometimes you may see this page if you are using advanced terms that robots are known to use, or sending requests very quickly.

IP address: 76.15.253.83
Time: 2011-03-06T01:56:17Z
URL: http://webcache.googleusercontent.com/search?q=cache:DnAklFIWnVUJ:ask-leo.com/why_is_my_browser_being_redirected.html+why+my+computer+was+redirectory+to&cd=1&hl=en&ct=clnk&gl=us&client=firefox-a&source=www.google.com

所有跟帖： 

• re-image, move to windows 7 -novtim2- ♂ (220 bytes) () 03/06/2011 postreply 22:21:03

• this IP address is at SUNYWCC, are you at Westchester Community -Windows8- ♂ (0 bytes) () 03/07/2011 postreply 08:37:18

• 回複：this IP address is at SUNYWCC, are you at Westchester Communi -supernav- ♀ (54 bytes) () 03/09/2011 postreply 15:21:37