This might seem concerning but it isn’t necessarily anything you’ve done wrong.
Google has a policy against “automated queries” which is software accessing their search results, pageranks, etc. to gather information. In search engine optimization you use tools which do this on a daily basis to keep track of how all of our client’s websites are ranking.
When too many queries happen too quickly from one IP address, Google will block that IP address from accessing it in order to protect it’s data.
IP addresses are shared by multiple people and will change so if you’ve received this message it’s entirely possible that someone else close to you was sending automated queries which triggered the warning. If you wait a while Google will eventually lift the ban and give you access to their websites again.
If you received this message and weren’t running any software which could have triggered it then it’s not a bad idea to run a virus scan since it’s possible that a virus on your computer could be sending automated inquiries. It’s far more likely someone else on your same IP address is though.
If you’re an online marketer who relies on software to make automated queries to Google in order to find keywords, ranking reports, etc. then I’d recommend a proxy service which routes all of your internet doings through another IP address elsewhere.