To protect yourself against identity theft and information security
threats, that can result from disposing of an old home or office PC.
You can prepare/"clean" your computer/FORMAT hard drive before
junking, donating, Trading in, or recycling it, to prevent your
most sensitive,personal, or business information from being
recycled right along with it...By REMOVING or,
LOW-FORMAT the hard drive first!

Even sending in for Repairs...

This is another way for an UN-scrupulous Repair Shop(or, their employees)
to copy your Personal Information, Credit, Social Security numbers, etc..
In this instance, REMOVE or Replace, with a "Sanitized" HARD Drive first!
A "sanitized" Hard Drive, is one that has ONLY the Operating System
installed on it(Nothing Else!) If they ask for it - Tell them to use
one of their own Hard Drives, also letting them know what
Operating System you currently use(OS).