Sony Xperia Pro is stuck in bootloop. How to fix?
So I guess the problem was either fixed or not solved.
But Just if anyone has the same problem it may be nice to know the solution.
I had the same problem and when I done the flashing the android would just start for around a second. We are using stock here, if you get a bootloop with an unlocked bootloader you should use fastboot to install a recovery or use the recovery.

So first you need to get Flashtool and find the right Firmware(ftf) for the phone.
I haven't found the exact same as I had before but It worked.

So when I first tried to flash it wouldn't let me I was getting a loader.sin error.So I Built a new ftf in Flashtool and removed loader.sin.
After that it flashed and started for a second just like yours.

After I did the same again an wiped all data it worked again.