Start Internet Explorer – double–click on the icon 
.
From the "Tools" menu select "Internet Options". 
Click on "Content" "Certificates ...". 
- In the field "Issued To" is the name to which the certificate was issued.
- The "Issued By" field shows where the certificate was issued from – Bank Service (B–Trust), Information Services – AD, etc.
- The field "Expiration Date" shows the date until which the certificate is valid – in the format DD.MM.YY.
In the specific example, there are two certificates installed.
The first is valid until October 20, 2004, and the second until August 23, 2005. You can get more information about the certificate by highlighting it and clicking the "View" button.
From the window that appears, the most important thing is that the picture in the upper left corner is green – this means that the certificate is valid.
If it is not green, but has a red sign with "X" thereon 
, it means that the certificate is not valid. Check the date until which the certificate is valid and if according to it it has not yet expired, but still the picture is red, it means that there is some other problem and it is necessary to consult with the organization that issued the certificate. The boxes "Issued to:" and "Issued By:" are analogous to the front screen – show in whose name and where the certificate was issued. 
The box "Valid from ...... to ......" shows when and until when the certificate is valid – i.e. the second date (in this case 23.04.05) shows how long the certificate is valid.
When you select "Certification Path", the hierarchy of certificates used by your certificate is displayed – these are the "ROOT" certificate of the organization issuing certificates – "Level 0", the certificate of the organization issuing the certificate – "Level 1" and finally – your certificate. All of these certificates must be valid in order to work with your certificate. If your own certificate is valid, but the ROOT or other certificate of the organization that issued the certificate has expired, you will not be able to work with your certificate. If any of these certificates is not valid – consult the organization from which you purchased the certificate. 
You can check whether these certificates are valid in a similar way – select them one by one and click on the "View Certificate" button.
Select the top certificate – in this case "B–trust Domestic Root CA – 2048 Level 0" and click the "View Certificate" button. 
In the window that appears, check if the image in the upper left corner is green and the date on which the certificate expires.
Then click the "OK" button and select the second certificate – in this case "B–Trust Domestic CA1 – 1024 Level 1" and click the "View Certificate" button. 
The steps are similar – check how long the certificate is valid. 
If all is well, click the "OK" button
Important:
- when viewing the certificate with "View Certificate" – a picture in green shall be displayed in the upper left corner of all certificates
- the date on which the certificate expires shall not be expired
If there are any irregularities in any of these points – contact the company from which you purchased the digital certificate or the computer specialist who maintains your equipment.