Do you have a Windows desktop or laptop PC that was fast when it was new, but has since slowed to a crawl?  Or one that is constantly popping up disk-full or error messages?  The usual cause of these problems is hard disks that fill up as you install applications and add data, or inefficient use of your PC’s available horsepower.   Before you replace that PC, try these fast and free cleanup and optimization steps.  Perform the steps in order (any step can be skipped), and reboot when prompted.  A caveat: there are as many cleanup routines as there are PC users.  I’ve refined the steps outlined here over the years.  They purposely don’t make major configuration changes or delete data, but are offered without warranty, for use at your own risk.  If in doubt, consult a specialist before making any changes to your PC. 

1.      Optimize available memory settings.  This step varies slightly between Windows versions and you may have to reach each function by a different route.  In Vista, for example, right-click Computer (on the desktop or from File Explorer), select Properties, click Advanced System Settings and select the Advanced tab.  Under Performance, click Settings.  Under Visual Effects, de-select all options except Smooth Edges of Screen Fonts.  Under the Advanced, Virtual Memory tabs, click Change, select Custom Size and set both Initial Size and Maximum Size of the paging file to the Recommended Total Paging File Size (found at the bottom of the window).  Select a single drive--other than c:\ if one is available--to hold the paging file.  OK all the way out, confirming changes.