You won't find a download link for RH8 anywhere. Out of interest did you deactivate it on your old PC? If not, you'll have problems reactivating it on your new PC anyway. Have you asked around for an install disk or download file? If you don't have it, check out this post: http://forums.adobe.com/message/4115458
Also don't forget to install both the 8.0.1 and 8.0.2 updates available at http://www.adobe.com/support/robohelp/downloads.html
You can get downloads of older versions through the Adobe Licensing site if you were involved with volume licensing.