Share your experience!
Any antivirus or taskilers?
how old is your SIM card?
is it a MICRO SIM card or did you trimmed a regular SIM card?
About the alarm thing,can you try settings-apps-all-alarms,force stop and clear data. Be careful that this should reset the alarms.
It seems that the Signal issue it's something you posted before
http://talk.sonymobile.com/t5/Xperia-M-M-dual/No-service-Problem-on-Xperia-M/m-p/728365
Uninstall any antivirus, battery app, booster app > restart your phone > report back
Repair the phone with PCC > report back
Bridge (for Mac)
Alternatives on How to backup Xperias
http://talk.sonymobile.com/thread/36355