Problem with my itunes - programme path cannot be found - can't uninstall

Hi I was wondering if anyone can help me...

I've got a problem with my itunes and I'm at a loss as to what to do!

I recently went to open itunes and as I did a message came up to say that itunes has not been properly installed and that if I want to burn cds etc, itunes needs to be properly installed. Firstly I don't understand why this message has come up as I have barely been on itunes over the past few weeks, in fact I've barely been on my laptop full stop. Secondly, when I have gone into control panel and then gone to repair itunes it says that itunes64msi path cannot be found, itunes is supposedly stored under my user and under 'app data' which is nowhere to be seen on my computer at all. I then tried to uninstall the programme completely and the same message came up. I then downloaded the newest version of itunes on the apple website but that couldn't be properly installed as there is already itunes on my system. I've also tried to remove the programme whilst in safe mode but haven't had any success.

SO confused as to what's gone on, don't understand how itunes is still a programme on my computer but appears to be wiped from my computer at the same time.

I'm running on a windows 7 64 bit operating system and if anyone could help me I'd be so so grateful!!