If your account has not been used for some time, for example 6 months or more then your account would have been Disactivated by IRCTC :
Then there is a simple process to Reactivate your IRCTC account.
Send the following details of your IRCTC account from your Email id registered with suspended account to care [at] irctc [dot] co [dot] in.
Click here for IRCTC Customer Care numbers.
Click here to recover IRCTC forgotten User Name or Login Id.