My Sony Ericsson says it's ready to be used with the computer, so why won't it sync?

[Saphire]

I recently had to get a new Sony Ericsson, so I made sure to sync my old one with my computer. It worked completely, but now that I have my new one, it won't sync. The screen (yes, of course I have the Sony Ericsson PC Suite installed) says that I have my phone in "Media Transfer Mode", so I cannot sync it. Following the instructions to a "T", I unplugged the USB cable from my computer, and plugged it back in again. My phone brings up a screen where it says "Phone ready to be used with computer", but after my computer screen is done detecting my phone, is says that my phone is still in "Media Transfer Mode". I was prompted to install the latest version of Java on the first try, and I did so. I rebooted my computer after it was installed, and tried syncing my phone again. A few more irritating tries of plug in phone, attempt to sync, follow instructions, (although it hasn't prompted me to reinstall Java, so that's good), end up still having it in Media Transfer Mode, rebooting, and doing it again, I decided to come here. Can someone help?