The instruction to put php.ini in your public_html folder and mod .htaccess didn't work? You don't need a restart for that.
This is a matter for your web hosting provider.
If you cannot edit php.ini && you cannot restart your services && you can't do anything that has been sugested && you don't know how it works; then you will need to contact your host and ask them to do it for you.
There is no other solution. I am assuming this is a shared hosting package.
Krönik Karbon's post in IP.Downloads "No file was selected for upload" was marked as the answer