You have a computer that is just not behaving right anymore and you are about to throw it out the window.  You’ve heard about formatting a computer and think, “This is the answer to my problem!”.  Well, when is it a good idea to actually format your computer?

Formatting a computer (and by formatting I am referring to a complete wipe of the computer, not just an operating system reinstall) is usually only done in extreme cases.  Formatting computers is a time-consuming process, and can cause quite a headache if all does not go smoothly.  When possible, it is better to fix the problem your computer is having rather than format it.  It will be worth your money to find a good computer person to fix the problem and avoid the hassle (and probably days of frustration without a working computer) of formatting yourself.  But, there are times when a format is a good idea.

You have contracted a serious trojan / virus / malware that you have reason to believe is stealing your personal information.  This is a concern for users who store a lot of sensitive information on their computers (think medical offices, accountants) that cannot risk having that data exposed.  If you are in this position and the consequences of stolen data would be detrimental, it is good to format that computer and start over.

You are giving the computer to someone else and want to clear off your information first.  Formatting is a great way to clear your computer of personal information so that future users cannot access it.  (Note: if you are donating your computer or do not know where it will end up, I recommend pulling the hard drive out instead of formatting to protect your data).

The computer is slow, and I mean S-L-O-W, and not feasible to work on.  Formatting will clear off the computer and make it like brand new again.  This is only recommended if you have tried other clean-up methods first to no avail, and should be done if you do not care about reloading everything back on but just want a new start.  Keep in mind that formatting will not speed up hardware, so if you have a dinosaur, the computer will only run as fast as its equipment will allow.

Your computer cannot boot, you get blue screen errors, something is seriously off, etc.  Most errors can be repaired without having to format, but there are errors out there (usually caused by a virus/trojan/etc. or by somone making changes and not knowing what they are doing) that can wreck havoc on a computer and the only way to get it back to normal is to format and reinstall.  Formatting will not cure hardware errors, only software issues.

As always, back up your data regularly so that if you do find yourself having to do a format, you will have an easier time reloading everything back on again.