Note: RaQuest needs Enterprise Architect. You can't use RaQuest without Enterprise Architect.

• Microsoft® Windows 2000 (32bit, SP4 or later), Windows XP (32bit, SP2 or later), Windows Vista(32bit)
• Enterprise Architect 5.0 or later version (RaQuest Version 2.3 or lower needs Enterprise Architect 4.1 build 737 (or later build), Enterprise Architect 4.5 or later version.)
• 20 MB of available hard-disk space .
• 1024x768 screen resolution preferred for showing lists and manipulate Requirement items - 800x600 useable, 640x480 not suitable.
• RaQuest can't use with Linux.

Link:
Enterprise Architect's System Requirements