1. A method of protecting a computer system, said method comprising: running an additional operating system on a virtual machine hosted by a first operating system having privileged access to the computer system, wherein the additional operating system has a lower access privilege to the computer system than the first operating system; preventing, by the first operating system, the additional operating system from writing to restricted portions of a memory of the computer system, wherein the restricted portions of the memory include a kernel of the additional operating system; detecting an attempt by the additional operating system or an application to write to the restricted portions of the memory, wherein the application runs inside the virtual machine and has privileged access to the virtual machine; and providing a warning when the attempt to write to the restricted portions of the memory has been detected, wherein preventing the additional operating system from writing to the restricted portions of the memory does not prevent the first operating system from writing to the restricted portions of the memory.