How can I solve "Error: MySQL shutdown unexpectedly"?

When I open XAMPP and click the start MySQL button, it gives me an error. I had started it just before, but now it isn't working. > 12:19:12 PM [mysql] Attempting to start MySQL app... \ > 12:19:12 PM [mysql] Status change detected: running \ > 12:19:13 PM [mysql] Status change detected: stopped \ > 12:19:13 PM [mysql] Error: MySQL shutdown unexpectedly. \ > 12:19:13 PM [mysql] This may be due to a blocked port, missing dependencies, \ > 12:19:13 PM [mysql] improper privileges, a crash, or a shutdown by another method \ > 12:19:13 PM [mysql] Press the Logs button to view error logs and check \ > 12:19:13 PM [mysql] the Windows Event Viewer for more clues \ > 12:19:13 PM [mysql] If you need more help, copy and post this \ > 12:19:13 PM [mysql] entire log window on the forums Here is the contents of the error log: > 2013-08-02 12:19:12 4536 [Note] Plugin 'FEDERATED' is disabled. \ > 2013-08-02 12:19:12 f64 InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed in future releases, together with the option innodb_use_sys_malloc and with the InnoDB's internal memory allocator. \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: The InnoDB memory heap is disabled \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Mutexes and rw_locks use Windows interlocked functions \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Compressed tables use zlib 1.2.3 \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Not using CPU crc32 instructions \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Initializing buffer pool, size = 16.0M \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Completed initialization of buffer pool \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Highest supported file format is Barracuda. \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: The log sequence numbers 0 and 0 in ibdata files do not match the log sequence number 1616798 in the ib_logfiles! \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Database was not shutdown normally! \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Starting crash recovery. \ > 2013-08-02 12:19:12 4536 [Note] InnoDB: Reading tablespace information from the .ibd files... The most important error message is here: > **2013-08-02 12:19:12 4536 [ERROR] InnoDB:** Attempted to open a previously opened tablespace. Previous tablespace *mysql/innodb_table_stats* uses space ID: 1 at filepath: *.\mysql\innodb_table_stats.ibd*. Cannot open tablespace *xat/payments* which uses space ID: 1 at filepath: *.\xat\payments.ibd* The rest of the log: > InnoDB: Error: could not open single-table tablespace file .\xat\payments.ibd \ > InnoDB: We do not continue the crash recovery, because the table may become \ > InnoDB: corrupt if we cannot apply the log records in the InnoDB log to it. \ > InnoDB: To fix the problem and start mysqld: \ > InnoDB: 1) If there is a permission problem in the file and mysql...