parallels and viruses

ok so i installed windows on a usb hdd using parallels. a few questions:

1. if windows and the virtual machine is on a external hdd, does windows utilize OSX structure and thus allowing open doors for windows viruses

or

since it is on an external, parallels and windows do not utilize the OSX structure.

2. i found a guide that someone wrote on installing windows on a hdd complete without parallels, but you must disconnect the hdd in the mac. I have a macbook pro and to get to the hdd you have to take out 47 screws and it voids the warranty. I'm not going to try that, but i wonder if anyone has heard of a way to disable the hdd without disconnecting it so this procedure can be done. THis way you have a full functioning windows OS on an external hdd.

here is a link to that guide: http://tubeshards.wordpress.com/2006/12/05/install-windows-to-a-macintosh-usb-drive/

Parallels makes a virtual disk that is read by the computer as a file. That being said, if you get a virus in you parallels windows session, it will only wreck your parallels session and cannot mess up OSX.

nukemm is correct. A Windows virus will not harm OS X. So there's no need to remove or disconnect hard drives.

Remember that viruses, spyware and malware are nothing more than Windows programs. They don't have mythical powers and in the same way a PC program will do nothing if you try to run it on a Mac, Windows viruses will do nothing.