Hi, wachuna.
1. Drop (Delete) a schema (database user) that it will not drop (delete) a tablespace, except you drop the tablespace.
2. To check whether a corrupt datafile exist, you can check it in database alert log. (or login sqlplus with sys / system, select * from v$recover_file

3. If you want to recover a data file and your database is in archive mode and you had full backup database before the datafile was corrupt, you can recover the tablespace with archive file(s).
a. To check whether your database is in archive mode by the following sql (login database with id sys or system)
select * from v$instance; and select * from v$database;
b. shutdown database and make a full database backup
c. copy the data file from the last database full backup
d. copy the archive files when you have delete the archive files. (all archive files which were created after last database backup until now).
e. login database with sysdba
f. startup mount (sqlplus command)
g. receover database (sqlplus command)
h. shutdown database
i. check alert log ( and check it by command : select * from v$recover_file

, if it is ok , make a full backup of database.
Hope this can help you.