[bawaji]

Have you unlocked your phone using Hard-SPL? You need to do that successfully before you can load non-stock ROMs. If you have, then disconnect the computer from the network, disable the firewall and antivirus and see if you can update the ROM on the phone.

Does the phone connect to the computer using ActiveSync? If you are even unable to get the phone to boot into a ROM anymore, try to get into the bootloader menu (pull the battery, reseat battery, hold volume down button, hold down red power button until you get to the tri-color screen), connect the phone to the computer with the USB cable, and load the stock ROM on it. Once the stock ROM works, you can try loading another ROM.