Hi Aleksandar,
Thank you for posting in Microsoft Community. I understand your concern and I am glad to assist you.
As per the description, I understand that you are getting an error “signature of this program is corrupt or invalid”. I will certainly help you in getting this fixed.
This issue might occur due to incorrect settings.
Try this first and check if the issue can be fixed other continue with the methods suggested.
Go to download manager of IE, find the file in the download list and the most important thing, right click that file. Click "
run it anyway ".
Let’s follow below mentioned steps and check if that helps:
Method 1: Disable software with invalid signature to run in Internet Explorer
a) Open Internet Explorer browser from Desktop.
b) From the menu bar select Tools Select Internet Options.
c) In the Internet Options window, select
Advanced tab.
d) Scroll down and un-check the Allow software to run or install even if the signature is invalid
e) Click OK to save the settings. Then close the
Internet Options window.
Try method 2, if the issue persist
Method 2: Reset Internet Explorer
Refer: What to do when Internet explorer isn't working
http://windows.microsoft.com/en-us/internet-explorer/ie-crashes-stops-working#ie=ie-11
Note:
The Reset Internet Explorer Settings feature might reset security settings or privacy settings that you added to the list of Trusted Sites. The Reset Internet Explorer Settings feature might also reset parental
control settings. We recommend that you note these sites before you use the Reset Internet Explorer Settings feature. Resetting Internet Explorer isn't reversible, and all previous settings are lost after reset.
Also if you have Microsoft Security Essentials, remove it and check if the issue is fixed.
Hope the information helps. Let us know if you need further assistance with Windows related issues. We will be happy to help.