I've boot with Ubuntu 12.10 boot able disk. I've selected Install inside windows option. PC has been restarted. Then My windows 8 started normally. But, the installation didn't started.
To install Ubuntu from within windows, you need to use Wubi.
To use Wubi, just download it from Here.
For morre info take a look at Installing Ubuntu from within Windows.
To install Along side Windows, just choose that option when you get to the installation type screen.
For Wubi installation instructions click Here
For other installation methods click Here
The following things may help you-