Opticraft uses old OpenAL. Windows 7’s OpenAL32.dll in SysWOW64 is likely missing or broken.
Instead:
Update drivers manually via the manufacturer's website; Windows Update often fails on Win7. Launcher Won't Start Switch to the Legacy Windows 7/8 launcher from Minecraft.net Screen Tearing in your Minecraft video settings or Optifine. opticraft minecraft windows 7 fix