In order for you to play Rhiannon: Curse of the Four Branches on Windows with minimal graphics settings, your computer must meet the following requirements
OS *:
Windows XP, Vista, 7, 8
Processor (CPU):
1.5 GHz Intel® Pentium® 3 or AMD® Athlon® processor
Memory (RAM):
512 MB RAM
Graphics Card:
64 MB DirectX compatible
DirectX:
Version 9.0c
Storage:
3 GB available space
Sound Card:
DirectX compatible Sound Card