I will guide you through how to put a portable Windows OS, a Linux standalone OS, A Portable Application Launcher, A encrypted section, and all the tools needed to analyze and fix a malware, spyware or otherwise inflicted computer.
What You Need...
1.) A External HDD these can be found decently priced almost anywhere. Newegg
a stupendous option.
2.) A copy of Linux. The best three are Puppy Linux
, Damn Small Linux
, and Webconverger
3.) A Licensed Copy of Windows. How you obtain it is on you.
4.) TrueCrypt freeware. Available here
5.) A copy of PortableApps. Available here
6.) A Portable Anti-virus scanner. I will be using Clamwin available free here