I have 4.7 GB still free out of 32GB.
I'm an running the latest firmware (4.3.3).
I have restarted the device many times.
But the iOS is very sluggish and it's slow connecting online. Definitely not as fast as it used to be. I also install/uninstall lots of apps. Is there maybe a way to clean up the hard drive?
You should clear out your multitasking menu. Double-click your home button (circle button) and it will bring up a row of apps along the bottom, tap and hold one of the icons until it has a minus sign and starts to wiggle. Tap the minus signs on all of the apps until they're all gone. All of those apps are essentially running as background processes and will slow you down if you have a lot.