First disable the Kaspersky firewall on one the PC's and retry accessing the router.
In the past I have found that a 3rd party firewall sometimes needs to be uninstalled to ensure that it has no effect on what you can access (mainly Norton though)
Unfortunately I am not familiar with that firewall so can't offer advice and how to allow an IP address or how to reset it.
The only way to reset Kaspersky to default setting appears to be remove and reinstall according to Kaspersky support https://support.kaspersky.com/12985#block2
although I would imagine that there is an option in the Firewall to remove any rules.
To edit the hosts file follow these steps:-
Press the Windows key.
Type Notepad in the search field.
In the search results, right-click Notepad and select "Run as administrator"
From Notepad, open the following file: c:\Windows\System32\Drivers\etc\hosts
Remove any lines that do not have an asterisk * at the beginning
Click File > Save to save your changes.
See if that helps
Edited by rogerfp (Mon 20-Mar-17 19:43:20)