Question : Spyware populating search history?

My company is an IT services provider.  One of my staff just reported to me that she was working on a client's computer last week that had highly inappropriate, offensive searches listed in the search history. She noticed this while she herself was doing a search and Google prefilled with past searches.  As I am struggling to decide what I will do with this information, I would like to hear if anyone knows whether it is possible that the search history may have been filled by spyware or virus. The computer definitely had some, as that was why she was working on it.  Now I am trying to determine which one may have caused the other.  Did the immoral searches cause the virus, or did the virus cause the searches?

Answer : Spyware populating search history?

Search history is saved by the browser in use - it's not cached by google or other search engines.

While it is plausible that the file in which the browser saves a search history could be tampered with,  I believe that it's more likely that the user got the virus(es) from inappropriate websites, rather than the other way around.

If you have a content filter such as websense or a firewall that saves recent web history, could you check to see if those websites have been visited while the user was at work?

If it's a laptop and they take it off-site, I would consider clearing the searches and viruses and then check the search history at a future date to see if they've returned, or installing a filter such as OpenDNS or a parental control software to block access to such sites.