katzka on "[Plugin: W3 Total Cache] can not delete plugin"

Hi i tried W3 Total Cache , the css js minimizing function broke my site, it broke my meta slider slideshow, than i desabled it and tried to delete but as soon as deleted it i could not log in to my wp-admin i got "service not available" on a blank page
fortunately i had a backup of the whole site and i moved back the w3-total-cache folders and the css and now it is working but the w3-total-cache did not the work, the site is slow, i can not try other plugin as i can not delete this one
Can somebody tell me why my site is "connecting" so slowly, how can i check where is the problem??

http://wordpress.org/extend/plugins/w3-total-cache/