.DLL

.DLL file extension

This is the basic program to work with .DLL extension

Windows Media Player

Windows Media Player Application Extension

Many people would agree that Windows Media Player has proven to be one of the most reliable and convenient tools to manage one's media library. There is a lot it can do: organize your files, play videos and music, burn CDs, stream your media to other devices... the list of features is very large and very impressive... (more)

The program works with the following extensions: mkv, mp3, mp4, ifo, avi, vob, dat, wma, flv, wmv, rv, mov, wv, au, qt, ts, aa, ra, wm, rm, tp, rp, rt, aif, m4v, vg2, axa, wmx, ape, mp1, axv, wmz, mpc, dvd, mpa, mts, uis, wpl, asf, mpv, wmp, mpe, ogg, wvx, asx, mqv, anx, ogm, vfm, 3g2, 3gp, pls, mpg, spx, esv, mps, m2t, xpl, cda, smi, rnx, rmi, ivf, m2a, snd, m4e, aac, msv, m1v, bin, dsf, wav, ac3, m2v, mmv, wax, ram, cel, m2p, m3u, dts, dff, flc, mid, flx, rmm, fli, k3g, ogv, wmd, m1a, rpm, mod, wms, m4a, mp2, mka, cdg, mp2v, aifc, aiff, mpeg, mpga, 3gp2, mpv2, 3gpp, smil, divx, flac, midi, rmvb, m2ts, 3gpp2, hdmov, xldap, dvr-ms, ratdvd and audiocd

.DLL extension is also supported by the following programs:

NUnit

NUnit Application Extension

NUnit is a unit-testing framework for all .Net languages.
NUnit-Net-2.0

NUnit-Net-2.0 Application Extension

CorelDRAW Graphics Suite

CorelDRAW Graphics Suite Application Extension

Create vector illustrations, edit photos, and create page layouts.
WinRAR

WinRAR Application Extension

Compress and e-mail files and folders using RAR and ZIP archive formats.
Yahoo! Mail

Yahoo! Mail Application Extension

Windows Essentials Codec Pack

Windows Essentials Codec Pack Application Extension

It's easy to use and even easier to install/uninstall.