Windows:

Ever notice how hard it is to find a SP on MS site? And even the full download one is hidden even more.

Windows:

DirectX Graphics and sound. Must have, and update often. LitePC Remove IE and other things that slow down your PC.

Windows XP:

Win XP SP2 the Full 267 mb download of SP2 for Windows XP. PowerToys for WinXP

Windows 2000:

Win 2k SP4 the Full 130 mb download of SP4 for Windows 2000.

Windows 98:

TweakUI adjust hidden options, menu speed, window animation, and MS IE. List of MS patches for 98

Windows NT:

Win NT SP6a