Removing the white screen can be very time consuming process! I mean finding the couse of it! I've been playing around a lot! So here what I did:
1. Delete plugin folder via ftp software (I use Filezilla) and all the other files like:
2. Delete WT3 additions in the wp-config.php - I deleted
define('COOKIE_DOMAIN', 'mysite.com'); // Added by W3 Total Cache
3. Find every .htaccess file in your site (I found two), from the wp folder to the site root, and remove the WT3 additions. I deleted this line:
# BEGIN W3TC Browser Cache
Header append Vary User-Agent env=!dont-vary
# DEFLATE by extension
AddOutputFilter DEFLATE js css htm html xml
# END W3TC Browser Cache
4. Install the plugin again. Upload and refresh.
Overall W3TC leaves a huge mess after uninstall! Even it's creator - Frederick Townes says so. So please do these 4 steps above and hopefully all will be fine. Try to install the plugin again - if no luck - use another one!