Unable to load google home page: 403 forbidden…

Google happens to be set to my home page in internet browsers I use. This afternoon, as soon as I launched IE and Firefox I was presented with this message: 403 forbidden…

We're sorry...

... but your query looks similar to automated requests from a computer virus or spyware application. To protect our users, we can't process your request right now.
We'll restore your access as quickly as possible, so try again soon. In the meantime, if you suspect that your computer or network has been infected, you might want to run a virus checker or spyware remover to make sure that your systems are free of viruses and other spurious software.
If you're continually receiving this error, you may be able to resolve the problem by deleting your Google cookie and revisiting Google. For browser-specific instructions, please consult your browser's online support center.
If your entire network is affected, more information is available in the Google Web Search Help Center.
We apologize for the inconvenience, and hope we'll see you again on Google.

To continue searching, please type the characters you see below:

(Here goes captcha window)

Well, since I’ve never experienced this before first thing I did was to scan that very PC for virus, spyware, malware infections. Of course Symantec Antivirus says that it’s up-to-date and everything is cool.

Using alternate virus detection programs rendered the following results:

Registry Keys Infected:

HKEY_CLASSES_ROOT\Interface\{2e9937fc-cf2f-4f56-af54-5a6a3dd375cc} (Adware.MyWebSearch) -> No action taken.

HKEY_CLASSES_ROOT\Interface\{741de825-a6f0-4497-9aa6-8023cf9b0fff} (Adware.MyWebSearch) -> No action taken.

HKEY_CLASSES_ROOT\CLSID\{147a976f-eee1-4377-8ea7-4716e4cdd239} (Adware.MyWebSearch) -> No action taken.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\SearchScopes\{56256a51-b582-467e-b8d4-7786eda79ae0} (Adware.MyWebSearch) -> No action taken.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Schemes\f3pss (Adware.MyWebSearch) -> No action taken.

Restarted PC and after that things seems to be back to normal. I'm not convinced that the malware infection found was the cause here though. Anyone has any thoughts on this?