possibly resolved, i will report back soon.
my hosting company has php 5.2.17 and 5.3.8. 5.3.x can only be used if “AddHandler application/x-httpd-php53 .php” (no quotes) is in the .htaccess file.
well, until this week that was working fine, but evidently something is wrong with their php 5.3.x because as soon as i commented this line the 2 sites worked 100% normally. one odd exception is when i logout of the admin side and just view it as a normal user. it gets ugly, but this might be a theme problem.
anyway, it might be solved!