Default htc desire mode auto after water and problem

the other day it went a little water to my htc desire froyo rom and I rode half an hour after I have left in acccensione fastboot screen ... blocked for 10 minutes and then restarts rom ... after a couple of hours the back button works more, and still reboot fastboot screen. I remove the battery and restart several times but after a while '... same problem ... with even more original rom does not read usb cable from pc and phone, when attacks cable does not detect it ... putting a rom cooked midway detects cable and usb mass storage .... but with original ROM by power-on auto mode active and if you call the part with the hands-free cell with the rom cooked .. no problem .. but I did not understand that it happened 'cause I can not replace more rom original file and I washed again with the usb and instead cooked crashes after a while?'ve flashed with various rome but nothing .. what can I change?