There is a good walkthrough for the original Windows version of the ChäoS;HEAd game at https://docs.google.com/document/d/1qZlVQvwCgKYa3gm8CbCC4f_WwxfTLHzKvbLekPMv5Mg/edit?usp=sharing, written by repgatu, edited by Fasty, with B ending information from MrMonday and RCgamer77. Please click the above link to view it (it is not hosted on this wiki).
If playing the original ChäoS;HEAd for Windows, be sure to use the Chaotic;Head 1.30 translation patch for the Windows version of ChäoS;HEAd (which can be purchased legally), unless you can read Japanese, in which case you should play the original game unmodified.
Also, did you know that Committee of Zero is doing a ChäoS;HEAd NoAH English translation and Windows port? We plan on either linking to or hosting a walkthrough for their ChäoS;HEAd NoAH fan translation, once it comes out.