Trying to update iPhone software, to 5.1.1?

I have the latest iTunes, and when I plug in my iPhone, and choose "check for updates" it comes up with a window for me to choose a file. Saying it has to be a.ipsw file. I have windows xp and hve an have iPhone software 4.3.

Try updating when you connected to internet. IPSW file will be downloaded by itunes only.

See https://discussions.apple.com/...5#18344405

http://dave.merten.mobi/fixit/

Try to just update it through your phone, not the computer. Go to your settings and there should be an option that says updates. You'll know what to do from there