I would suggest checking for some registry settings and if you have any variations from the default value you may change them to default and check if the issue resolves –
1. Choose Start and then click Run, and type regedit in the Open text box then click OK.
2. Open the key -
HKEY_CURRENT_USER\Control Panel\Desktop.
3. Now in the registry editor window in the right pane you will find the keys Foreground Flash Count and Foreground Lock timeout.
Refer to the below links and check for the default values on your computer. Check if you have the same values as mentioned in the below links -
http://technet.microsoft.com/en-us/library/cc957205.aspx
http://technet.microsoft.com/en-us/library/cc957208.aspx
If the values differ from the default values you may double click the names and change the values. Make sure you make the decimal selection and then change the values.
REGISTRY EDIT DISCLAIMER:
Important: This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows:http://support.microsoft.com/kb/322756
Hope this helps.