What anti-virus software are you using?
If you're just searching for a word (regardless of what that word is) and your anti-virus is activated, I suggest...
a) Don't log in to any secure websites
b) Make sure your anti-virus is updated and perform a full-scan
c) Perform an anti-malware scan (such as [safer-networking.org...]
d) If none of the above work, change browser
I'll take a guess and say its some form of malware installed on your system that is tripping the virus detection.