Internet Explorer uses digital certificates to scan and authenticate servers and clients across the web. This ensures that your browsing is secure by verifying the legitimacy of businesses, people and organizations on the Internet. Digital certificates can be restored if they are deleted. Because you do not know who to trust online, restoring deleted certificates ensures that you are protected from online predators, who pose as legitimate groups and business.
Open Internet Explorer and click "Tools" from the main panel. Scroll down and click "Internet Options."
Click the "Content" tab on the options window, then click "Certificates." Click the "Import" button and follow the certificate import wizard to load a deleted certificate. Certificates are stored in Certificate stores. These stores are located in the registry under these keys: HKEY_LOCAL_MACHINE\Software\Microsoft\SystemCertificates and HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates. They can also be located in the following folder: C:\Documents and Settings\user name\Application Data\Microsoft\SystemCertificates\My\Certificates
Enter the password for the certificate file when you are prompted to, then check both the "Enable strong private key protection" and "Mark the private key as exportable" boxes.
Click the "High" security option when prompted to in the private exchange key window. Click 'Next."
Choose "Create a password for this item" and set your password. Enter the password you just assigned. Click "OK" to complete the importation of a deleted certificate.