"Welcome to TinyApps.Org, a guide to very small software for your PC. Virtually all of the programs listed here are free of charge and for use under Windows. If this is your first visit, please read the FAQ."
Check them out at:
http://www.tinyapps.org/
The apps there are all written to be as small as possible, size wise, memory use wise, etc.
They've got a web browser that's 1.1mb in size.
a 42K ad blocker,
4k text editor,
5k CD player,
219k mp3 and wav player,
133k Media player supporting many formats and several OSs
Mpxplay 1.46 [223k] {S}+ DOS based (32-bit) audio player. Supports: MP2, MP3, AC3, OGG, MPC, WAV, CDW.
foobar2000 v0.667 [334k] + Simple yet powerful audio player with support for MP3, Ogg Vorbis, MPC, FLAC, Ogg FLAC, WAV, MOD, more.
CDex [1285k] {S}+ Rip CDs to WAV or MP3, convert files between WAV and MP3, more.
Audacity 1.0.0 [1290k] {S}+Audio editor that can record/play sounds, import/export WAV, AIFF & MP3 files, and much more. Windows, Mac, and *nix versions available.