Flashing Wont Help You.
Do One Thing.
Flash Using Old Firmware Via SEUS (Reply If You Want Method)
Then Upgrade You EROM Via Downloading Wotan Client From Online de-branding and software upgrade service SonyEricsson (SE) mobile phones | WotanServer.com
Let Wotan Update. Then Clear Login And Pass And Press Start.
Next Attach Your Phone By Pressing 2+5 Keys Instead Of c.
Let It Update Your EROM.
This Will Take 11 Seconds.
Now Update Your Firmware Using Legal Method, i.e SEUS.
Although This Take About Haf An Hour But Will 100% Run Your Phone Smoothly.
Guranteed