a very common thing is to include a restore CD and not a factory WINDOWS CD
for the most part all the same shit would go right back onto the machine
The best thing to do, is buy a computer keeping in mind that software is free so don’t get any software packages with the computer.
Take this computer once it ships to you to someone that knows how to secure a computer, and is willing to help out. Have this person start from scratch. Format, install OS, set up auto updates for windows and antivirus software. There a good portion is done.
Now people have to realize when something is presented to them if that is a threat or not. Then basic usages of a few others programs. You will be trouble free for a while.
PREVENTION!