Your computer is ancient. Namely, its a Pentium I from before MMX (multimedia extension) was ever introduced. Go to
http://www.winampheaven.da***** and get a version of Winamp like 2.666, install it over your current version, make a backup of the file
C:\Program Files\Winamp\Plug-ins\VIS_AVS.DLL
and reinstall Winamp 2.77. Then, copy your backed-up VIS_AVS.DLL into
C:\Program Files\Winamp\Plug-ins
again. You will have to copy the old VIS_AVS.DLL into the folder every time you install a new version of Winamp if you want to be able to keep using AVS.