IPhone downloading iOS7 problem?

So I went to download iOS7 but I had too much stuff so then I started deleting stuff but after I deleted the last app both my home and lock screen have stopped working.

You need to reset the iPhone. Here's how:
An iPhone reset or reboot should not normally remove
or delete any data or settings. However, the term reset
is also sometimes used to mean deleting all content
from the iPhone in order to start over fresh with it
and/or restoring from a backup. If you read
instructions that mention reseting the iPhone, make
sure you know which kind of reset you'll be performing
and plan (and perhaps back up!) accordingly.
Affected iPhones
This reset process works on the:
For More Help
Restore to Factory Settings: If you want to wipe all
the data from your iPhone and start from scratch (this
can solve some tough bugs and is also good if you're
going to sell your iPhone), try restoring it to factory
settings.
Recovery Mode: If your iPhone is stuck in a reboot
loop, or won't boot past the Apple logo, try recovery
mode.

1. Begin by holding the sleep/wake button at the top
right of the device and the Home button at the
bottom center of the face at the same time.
2. Hold them both until you see the screen go black.
In some cases, you may need to keep holding them
even after the red power-off slider appears. If it
appears, just keep holding it.
3. Wait until the silver Apple logo appears.
4. When this happens, you can let go - the iPhone is
rebooting.