Method 1: You may perform a SFC scan and check if it lists any issues.
ToPerform a SFC Scan -
a. Click Start, click All Programs, click Accessories, right-click
Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click
Allow b. Type the following command, and then press ENTER: sfc /scannow
A message will appear stating that 'The system scan will begin'. Be patient because the scan may take some time.
c. If any files require a replace SFC will replace them. You may be asked to insert your Win7 DVD for this process to continue.
d. If everything is okay you should, after the scan, see the following message "Windows resource protection did not find any integrity violations".
e. After the scan has completed, close the command prompt window, restart the computer and check.
You may check for errors in the Event viewer and if you are getting any, do let us know the details. To open event viewer follow the below mentioned steps:
a. Click the Start button then click
Control Panel in this click
System and Maintenance. b. Now click
Administrative Tools, and then double-click
Event Viewer. If you are prompted for an administrator
password or confirmation, type the password or provide confirmation.
c. Click an event log in the left pane.