Follow these steps to clear out the Safari cache:

1. Press Settings > Safari.
2. Scroll down and tap Clear History and Website Data.
3. Tap Clear History and Data.

To perform Hard Reset do the following:

1. Press and hold the Home button (big circle below the screen) and the Sleep/Wake button (on top of the iPhone) simultaneously.
2. Hold both buttons until the iPhone shuts off and begins to restart.
3. Let go when you see the silver Apple logo appear on screen.
4. Congrats! You made it.
IMPORTANT: A hard reset is not a factory reset or restore - you won't lose any of your data.