500 internal server error

I had godaddy hosting, windows server running somewhat okay, then I switched to linux hosting and I have 3 domains with godaddy on linux shared hosting. Right after I installed the linux hosting I began getting 500 internal server error’s, not often but enough ( 95% of the time site works perfectly)

My .htccess file

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

any clues to what might be wrong?
Also I have the plugin WP-Supercache and I heard there might be problems with it.