I borrowed from my colleague a notebook computer for 14 days during official trip in India (now the notebook is in India).
I just come back and pop up something in my mind.
I used this computer to process a "VERY VERY CONFIDENTIAL" document in the first day of the trip (origin data stored in my external hard drive). In the following 13 days, I utilized this notebook computer to watch 9 different DVD and browse internet (6 hours per day).
I am not sure if his computer would auto-delete the data in virtual memory after reboot.
1.Will my document still exist in his computer (virtual memory)?
2. Has my usage of computer (i.e. watching DVD and browsing internet) already overwritten my confidential document in virtual memory?
3. Is ALL the data in virtual memory "first-in-first-out"? i.e. the existing information in virtual memory MUST be utimately overwritten by new-coming data when the computer keeps on being used ( That is blessing for me).
Here is what I do: I have a USB drive (a small 250 GB drive) with Portable VirtualBox installed, and a two virtual copies of XP on it. One copy of XP I keep clean to do things like you did; to work with private files. It also uses full disc encryption in case it falls into the wrong hands. The other I use for browsing possibly unsafe sites when doing research. This copy can be thrown away and replaced if it gets infected.
By doing this it is like I always have a safe computer to work with and my own files are safe, but I only carry a small USB drive!