About Windows 7 RTM MUI Language Packs

MUI stands for Multilingual User Interface.
There are full (%) and partial (80% according to Microsoft) MUI language packs.
Full languages change entire Windows 7 environment, partial languages lack some localization and the untranslated user interface is always in English, regardless of the original Windows 7 display language:

• Bootloader: Multi-boot menu, Safe menu options, Memtest
• Administrative Tools: Task Scheduler, Event Viewer, Services, Advanced Firewall
• Group Policy (Windows 7 Professional/Ultimate only)
• Some help files

You can use these language packs in bit Windows 7 RTM only (original release without a SP).
Upon installing specific MUI languages, you can install additionalLIP languages on top of them.

To find out your system properties (32/bit, SP installed or not) go to Control Panel -> System and Maintenance -> System or right-click the Computer icon in Start menu and select Properties.

Download bit Windows 7 RTM MUI Language Packs

(direct links from Microsoft: size varies from 29 to MB)

Download bit Windows 7 RTM Chinese (Taiwan) MUI Language Pack

(official language pack, not available from Microsoft due to political reasons)