I had a similar page when I typed in adsense, the error page was so basic and primitive, I think the old logo was present : http://www.google.com/adense You'd think they'd have a good error page or referred to a search maybe.
Google bans certain patterns of search content and approach. It happened after some trojans from infected machines tried to connect google.com and search for more infected hosts. For example, after some new WordPress bug, some trojan might have a function to: -open google -search for "powered by wordpress" -test for vulnerability -if positive - add malicious redirection code into the webpage Happened to me many times, especially when you make some complicated search using search operators and quickly browse through results jumping every 3 pages forward. Google thinks it matches non-human behavior and set this kind of ban. Try to avoid it be making your search a bit different, spend more time on search results, click links etc.
I just think that you have a virus or something similar in your computer. have you scanned your computer ? If you haven't I think you should do it as soon as possible