When I try and Access my Windows 7 OS I get the following memo and I have no idea what to make of the code.

Error mounting /dev/sda2 at /media/name/Windows7_OS: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sda2" "/media/name/Windows7_OS"' exited with non-zero exit status 13: ntfs_attr_pread_i: ntfs_pread failed: Input/output error
Failed to read NTFS $Bitmap: Input/output error
NTFS is either inconsistent, or there is a hardware fault, or it's a
SoftRAID/FakeRAID hardware. In the first case run chkdsk /f on Windows
then reboot into Windows twice. The usage of the /f parameter is very
important! If the device is a SoftRAID/FakeRAID then first activate
it and mount a different device under the /dev/mapper/ directory, (e.g.
/dev/mapper/nvidia_eahaabcc1). Please see the 'dmraid' documentation
for more details.

What should I do ?