check the health of your hard disk

1. Using Windows 7 Error
Checking Tools
Sometimes when we found a problem, we tend
to install third party applications and forget
about the basic tools that come bundled with
Windows. Unknown to many, many complex
issues can be easily fixed using programs that
are part of Windows operating system since
its first release. A simple interface doesn’t
mean it is a useless utilty.
First, double click “My Computer”.
Now select the drive you want to inspect and
right click:
Go to tools tab, and click “Check now…” :
Now, check that you select automatically fix
and scan for bad sectors:
If Windows cannot perform the checking
because the disk is in use, it will ask to
schedule the next time you start your
computer.
2. Using Windows 7 Recovery CD
Other way to check your hard disk is using the
Windows 7 Recovery CD. These tools can be
found in the Windows 7 CD or with a System
Repair CD. 
You can use this CD to look for problems in
your hard disk. You have to boot your
computer with this CD. Once you have
selected your language, you will see a window
asking what tool you want to start. In this case
we are going to use the command prompt:
Once you do that type “chkdsk c: /R ” and
press Enter to launch the application:
The verification process has 5 stages.
CHKDSK verify files, indexes, security
descriptors, USN Journal, file data and free
space.
3. Using System File Checker
Not all files in your computer are essentials for
your operating system. System File Checker
will check those files and solve any integrity
problem.
Use the find utility in the start menu. Type
“cmd” , rigth click and select “Run as
administrator”.
Now in the command window, type "sfc /
scannow" and press Enter.
The result will inform you if there is any
integrity violations.