Microsoft is willing to install a clean copy of Windows in its retail stores on any PC for a flat fee of $99. (Windows license not included, of course.) They’ll also optionally include Microsoft’s Windows Live Essentials programs, the ad-supported starter editions of Word and Excel, Microsoft Security Essentials antivirus, and Zune media player software.
There’s no question a bloatware-infested PC straight off the shelf will benefit from this, and a $300 PC receiving this treatment will almost certainly run better than an unmodified $400 PC running in its factory configuration.. For that matter, it might run better than an unmodified $600 PC.
But you could also just reinstall Windows yourself. And if you’d rather not take the time to reinstall Windows yourself, you could run PC Decrapifier and clean out your ghost device drivers, and probably get most of the benefit in about as much time as it would take to disconnect your PC and haul it out to your car.