Well i got a question, Do those Google/MS/famous computers has an buy-able antivirus(McAfe/Kaspersky)? or they build their own?
And do they build their own machines or buy 'em?

Google is a search engine.

MS= Microsoft, a company that makes software.
Microsoft doesn't build computers> their software, including the Windows operating systems are loading on computers made by different manufacturers.

Computers are hardware. They are build by several companies. Some of the microchips used may be made elsewhere and incorporated into their computers.

You can find information on Microsoft Security here: http://www.microsoft.com/security/default.mspx

You should get some computer references so you understand the difference between hardware, software, search engines and available security.

No, you missunderstood me. i meant, that those google computers, who runs the search engine(there are several,yes?) they MUST have some antivirus programs. so my question is, do they buy them from kaspersky etc. or make their own?

Well, I think the communication is missing:

First, there are NO Google computers.

Second, Google is a search engine and it can be used from any computer. Google has also made some software programs that the computer user can download. None of these are security programs at his time, as far as I know.

Third, neither Google or Microsoft are responsible for the security programs the owner of the computer CHOOSES to have.

Fourth, security programs are made by numerous software companies.

Fifth, those companies then license the use of their programs to the PC owner OR make arrangements with the computer manufacturers such as Dell, HP, Compact, Acer, and so on to pre-load them on their computers before sending them to the person who bought the computer.

You do not understand the concept of a search engine. From Wordnet:

Now i get it thanks for the very good explanation

There are google computers, where do you think you are connecting to when you go to www.google.com ?
I think bielius was asking what AV protection those servers run.

I don't know the answer to that, but since they are likely running on top of a UNIX environment I wouldn't be surprised if they didn't have any AV at all. In fact, I'd be more surprised if they did.