Nokia 6500S , phone is very very slow

It seems that your phone and/or storage card memory is full or almost full try to delete some file and free up some space from phone memory once you do that switch off the phone and start it after 2 min.
it will work fine.

I use LEO Privacy to boost my phone, too! a really useful app. It help to boost the system and other nice features. And I like its photo capture system to find out the snoopers.

I think you can have a try with LEO Privacy app. It can speed your phone and hide your stuff. Really cool for phone security and protection. LEO Privacy Applock Boost Hide Android Apps on Google Play