As new generations of computer operating systems and productivity software become more and more demanding in terms of minimum hardware requirements computers tend to become "obsolete." They're not necessarily broken -- just unable to meet the latest demands. Similarly, as a Windows installation "matures," the system disk tends to fill up and the Windows registry tends to grow to unwieldy and sluggish proportions. Applications like CCleaner can help, but eventually you'll probably reach the point where impatience and frustration levels have you scanning big box electronics store flyers. But wait! Before you buy (or even after you buy) consider this. If you mostly use your computer for surfing the web, email and some word processing and spreadsheets there may be another solution. There are a number of light weight, free and open source solutions that can turn a sluggish older Windows computer into a very serviceable platform for those requirements. And the speed will probably have you wondering if someone secretly upgraded your hardware. When you add in the fact that these lighter Linux-based operating systems are far more malware-resistant than any Windows installation and the extensive on-line support and developer communities behind them, you've got a win-win-win situation. On up-to-date or maybe one or two generations old equipment, we suggest Ubuntu Linux. Ubuntu is a well supported and maintained up-to-date operating system. A lighter weight variant, Lubuntu uses a less demanding desktop environment, and a selection of light applications which focus on speed and energy-efficiency. Because of this, Lubuntu has lower hardware requirements. Or you might want to check out the "Which Linux Distribution Is Best For Me" to explore a wider range of options and match them your requirements. And, by the way, if there are Windows applications you can't live without, there are options there as well, including WINE, a compatibility layer for running Windows programs under Linux, or running a Windows virtual machine through Oracle VM VirtualBox or one of several other virtualization options. And if, after considering all the options, you decide to try Ubuntu, here's a handy guide to making the transition from Windows: http://www.makeuseof.com/tag/migrating-from-windows-7-to-ubuntu.