why not just buy a cheep sh!tty laptop just for editing.
thats what i did for DJing, crappy laptop which just had music on and music related software which i could plug into my mixer or do what ever i want with.
buy a cheep laptop for £50. doesent need loads of fancy antivirus etc, just never conect it to the internet, download gimp or ps then once you shoot download pic onto said laptop and edit away. then every few months do a virus scan using something like avg just to make sure...