There's also ComboFix which can squash quite a few things ...
-4wd
Including your OS if you don't know what you're doing, or get a little too careless when attempting to fix things CF reports but doesn't handle automatically. 
-40hz
Hence the reference to "if you're going to re-install you might as well"

-4wd
Yes, but here's the "fun" part. Many (read most/all) of the off the shelf machines, that don't come with install media and use a recovery partition. Also use a highly proprietary boot sector that provides the press hotkey 'X' to get to brand X's recovery partition. This means that anything that does any cleaning of said boot sector has a highly probability chance of frying said functionality right off the disk. ...Yes...I see this happen a lot.
So like 40hz, I too have seen combofix torch a machine (from a consumers perspective) in the process of cleaning it many times. Scratch building the boot sector isn't the slightest bit fun on these new OS's because it has gotten a hell of a lot more complicated from the good old SYS C: days.
I had to do a production server transplant not to long ago from one MB with an SSD to a second MB with RAID1. It got done...but it took quite a bit longer than the initial estimate.
