I recently got a new computer with Windows 8, and re-installed Photoshop 5.1, Photomatix Pro, and Nik Silver. But when I go into Photoshop, I can't see Photomatix or Nik Silver. I've moved both of them to the Plug-Ins folder and then rebooted, but it doesn't seem to help. Any advice would be appreciated.
Did you check with the developer to see if they have updated versions of their plug-ins for Win 8?
Could be permissions issues or general compatibility issues with Win 8. As suggested, check with the vendors.