"Windows Rot" is the name someone gave the process by which a Windows machine becomes progressively slower the longer you use it and the more software you install on it.
I think I'll have to reinstall XP since the Windows Rot has slowed it down so badly...
Windows rot is a colloquialism encapsulating the belief that computers using various versions of the Microsoft Windows operating system suffer incremental and inevitable degradation of responsiveness and performance over time.
Windows users complain about having to reinstall their operating system when suffering Windows rot, because they are are unable or unwilling to invest in the time sink of many frivolous tasks necessary to maintain a healthy system.
The deterioration of performance that occurs in the vast majority of Windows installations for no reason.
Curing Windows rot requires that you reinstall the operating system from scratch.