Device shows in device manager but not disc management

So, I have the sony ericsson c510 and plugged it into my laptop (with windows 7). To transfer music sony ericsson advised to download Media Go. I plugged the phone in and could transfer music. The second time it told me the device is not recognized. I tried a couple more times and now it is somehow recognized but does not show in my computer. It does show in device manager and has all the updates but it does not show in disc management. In device manager it tells me that it should be on :I but in disc management :I is apparently offline.

Im confused... Help?