QuickTime Alternative will allow you to play QuickTime files (.mov, .qt, .3gp and other extensions) without having to install the official QuickTime Player.

K-Lite Codec Pack is a collection of codecs, DirectShow filters and tools. Codecs and DirectShow filters are needed for encoding and decoding (playing) audio and video formats. The K-Lite Codec Pack is designed as a user-friendly solution for playing all your movie files. With the K-Lite Codec Pack you should be able to play all the popular audio and video formats and even some rare formats.
K-Lite Codec Pack always very up-to-date with the newest (and/or best) versions of the components. The installation is fully customizable, meaning that you are able install exactly those components that you really want. Uninstallation removes all files and registry entries created by the pack. It is extremely easy to make a fully customized unattended installation. It tries to avoid potential problems with existing codecs and even fixes some problems.
The pack is able to detect broken codecs and filters on your system, and remove them for you.
It is a very complete package, containing everything you need to play your movies. Suitable for both novice and expert users. The K-Lite Codec Pack is compatible with Windows 2000, XP, 2003, Vista, and Seven.