Does reinstalling OS on computer clear viruses, etc??

[Natasha23]

Hey,
I have a 3 year old Toshiba laptop that I was having problems with.  Every time I tried booting it up again I kept getting error messages, so I decided to reinstall the entire operating system and wipe it clean.  I know they say that when you reinstall, it sets the computer back to how it was from the manufacturer, but does it really clear off any lingering viruses or worms, etc that could have been on there?  I don't intend to ever use this computer again on the internet so it won't be at risk for any new viruses.  I just want to make sure it's clean before I use it with my scanner.
Thanks in advance,
Natasha

[Gunner80]

Yes. Reformating is the best way for reinstalling an OS.

[Where is Hassan Nasrallah ?]

depends, there are bios virus that stay in boot.
i doubt you have one of those.

[crow316]

But doesnt that make you lose about 3 years of updates and upgrades?  Why not take it in to someplace to clean it up for you, it can be done relatively cheap.

[Genesis]

Reformatting should remove any viruses (except some obscure ones that are specifically written to counter this). Reinstall and scan it with your up-to-date scanner and that should take care of everything. Make sure all your media are free from viruses as well, or you'll just end up reinfecting your machine.

[25]

Why not simply run anti-virus, anti-adware and anti-spybot programs to disinfect your machine and then reinstall the OS (without formatting) to make sure that the problem isn't missing or corrupted files? You can get free or trial versions of Ad-Aware, Spybot S&D, and ZoneAlarm Security Suite online, which would take care of nearly every problem the average user is going to encounter, I don't see why anyone would jump straight to reformatting before trying all of those options. I wouldn't fancy the prospect of having to update all of the software and drivers I'd accumulate in three years (but I also wouldn't like using a three year old computer for anything other than parts). 

[MadmanDan]

 The best way is to completly wipe out your hard drive (format it) and then install windows. The XP CD can do all that.

  But remember to back up your data on CD's or DVD's