dns issues

Hello guys, after a couple of long hours, I've comed to the conclusion that the DNS server cache of my router is corrupt, and am looking for a way to flush it (see more details in the following paragraph). For the last two months, I've been unable to accesss a particular website...

Good Day All.. I have been chasing an issue with DNS where on the cmd line from the router DNS could not resolve addresses. Also the check for update was not working correctly and the VPN status page had an extreme lag to it.. My setup is as follows.. DNS/DHCP is provided by a windows server...