Type:CHKDSK C:
and press ENTER.
This activates a volume check in read-only mode (no changes are made). The process may report errors, as per:
Windows found problems with the file system.
Run CHKDSK with the /F (fix) option to correct these.
However, this is normal on a volume which is active, it is not necessarily cause for alarm.
After performing the check, the statistics will be displayed:
151681015 KB total disk space.
147658212 KB in 141079 files.
74296 KB in 25724 indexes.
16 KB in bad sectors.
353815 KB in use by the system.
65536 KB occupied by the log file.
3594692 KB available on disk.
4096 bytes in each allocation unit.
37920253 total allocation units on disk.
898673 allocation units available on disk.