No sim card detected? my SE Xperia Arc S started going crazy today, it didn't detect the sim card, so I've tried reseting the phone to factory settings, but it still wasn't detected, I've also installed a new rom, to no avail. Is there any way to fix this or do I have to get a new phone?

NOTE: the sim card works in another phone, other sim cards are not detected in mine either.
try installed some sim utility app like https://play.google.com/store/apps/details?id=com.androidyou.simcardinfo&amp;hl=en

then check the reading there. 

if still no luck, the sim slot of the phone might be broken. in this point , it's a hardware issue.