Ah! Okay, that's sure different from suggesting earlier that a format is anything but a last ditch effort. Yes, I agree that a format is a viable option in some cases for malware removal - but those are certainly not the norm, but for extreme cases - just as with hardware failures. There are always exceptions to the norm, and the norm is that most PC problems, including malware infestation, can be resolved, often with the help of qualified experts (whether hardware, OS, networking, malware, etc.) without a format and reinstall of the OS.rootkit/backdoor trojans are the only thing where I see referals to a reformat as the best possible option for security reasons
It is important that we as providers here ensure folks reading understand the substantial consequences of formatting the hard drives - that it is no trivial task to set up a new OS install - especially if there is a lot of proprietary hardware, such as with notebooks - install all new defenses, networking/Internet, email - a lot a work to setup a new PC. Even if you were wise enough to have a current backup, I have seen many reformatted hard drives get reinfected once the user restored all his data from his backup/recovery media.

The point is, you try all else first. Otherwise, you learn nothing, but how to install an OS. As for the referals you are seeing, please, heed this advice, if any one (expert or not) recommends a format at the beginning of the troubleshooting process, find another "expert"!
As for rootkits, note there are some rootkits that can survive a format - ready to reinfect again as soon as the OS is loaded up. So in that case, a format is a waste of time, on top of all lost data and updates - and customizations that make a computer "personal".