I cannot update my pc to itunes 11.1, i have tried it via itunes, and by plugging my phone in

Hi, GianSande.

Thanks for the question. Start with completely uninstalling iTunes and all of it's components in the order specified in the article below. Once this is done, download and install iTunes.

Removing and reinstalling iTunes and other software components for Windows Vista, Windows 7, or Windows 8

http://support.apple.com/kb/HT1923

If you receive any errors when uninstalling any components of iTunes, try the steps in the article below for each component that gives you an error.

"The feature you are trying to use is on a network resource that is unavailable" alert appears when removing Apple software in Windows

http://support.apple.com/kb/TS3704

If you experience issues during installation, see the article below.

Trouble installing iTunes or QuickTime for Windows

http://support.apple.com/kb/HT1926

Regards,

Jason H.