content: not exactly. android is run from an image that is basically static, with a writable region being the user space and for system configs and such.  anything goes wrong, wipe the userspace/systemconfigs and fresh install.  you can't do that on windows/linux/mac without some special setup (possible on linux.. dunno about the other two) windows system resides in the same userspace as everything else.  therefor it can be changed, altered in ways that you can't on the android. viruses can't infect android in the same way as a pc...   mostly because of the readonly nature of the system prevents major changes.