JunkWare in Windows
Windows XP has two really heavy-duty machine time wasters installed by default, ctfmon.exe & sapisvr.exe.
If your computer is too slow, they are frequently the cause of the problem. To remove them, follow the instructions given my Microsoft at these sites:
http://support.microsoft.com/kb/q282599
http://support.microsoft.com/kb/Q316215#XSLTH3127121124120121120120
