I am wondering if someone could tell me how can I set 1 Windows account and access it from multiple Windows 7 computers.
In our school every 1 has got own username and password and with that account we can logon to any computer in school and access our personal files.
Is this possible through some servers or something?
The setup that you are describing is known as a Domain, or an Authentication Domain. This is a mechanism of authenticating a user's credentials against a network service accessible from the entire network (domain authentication) rather than locally (machine authentication).
Microsoft's software solution is called Active Directory Domain Services, abbreviated AD-DS. A basic installation is available with all versions of Windows Server 2008, 2008 R2, and 2012. If you are a post secondary student you should be able to get access to this for free.