I just LOOOOVE to do a low level format! i use Kill Disc then put the OS (7 64 bit) on it, i format my pc's around 4 times a year, before i do the format i unplug everything then blow all the fluff and dust out of them and give them a basic dry clean and clear up any clutter...its a no loose situation...

Never with Win7.

But, once every six months or so, I sit down for a full day and go through the machine from top to bottom removing any programmes, files, broken shortcuts etc., which I no longer need. I back up the registry and then use Malwarebytes to check the whole system thoroughly. I also go through all the programmes running at boot using Soluto and alter as necessary.

Once a year I open the case and give the inside a clean using a vacuum cleaner and attachment, make sure all cards are seated firmly and that all the fans are spinning up when power is applied.

After that....I go down to the pub!!

I don't format any more. I clone to a USB hdd disc in an enclosure. Once a month, if I remember. Not being in a business then it really doesn't matter.Backups are to DVDs and flash drives and another hdd. Oh, I forgot, I usually buy a cheap laptop as another backup to my worshiped desktop.

in w98 and xp did it once a year, around xmas time. since vista & w7 had no need to they do not get sluggish with time.

I've found myself just not installing so much software as time has gone by, although I can see peoples points that W7 seem far less susceptible to getting bogged down. If I need to reinstall everything, it's done from a backup image and is quite quick and painless. Personal files are kept and backed up separately.