Sometimes cables/ports go bad, and maybe there isn't enough "juice" flowing through the cable for Winblows to recognize it as an iPhone? I'm just guessing here.
And I forgot to mention it worked last week and I never said it didn't work at all. The computer knows its plugged in, it just doesn't see it as an iPhone. If I go to device manager and plug it in it says iPhone for a split second then goes to mtp USB device.
Who said that it didn't work at all? Not me either....
So you were able to sync last week...any update to Windows or anything since then that might have changed something?
Which version of Windows and which service pack? Not knowing Windows at all, and reading what you said about it saying it is an iPhone then switching over to USB device, it sounds like something has changed with your windows. Something new installed or deleted...don't know.
I'll leave this here for just a bit longer to see if we can rule out iTunes, but I'm really thinking this is a Windows/Hardware (PC) issue, not an iPhone one.