From the limited information provided, I presume that your ISP router has an IP address of 126.96.36.199 , you should remove the existing default route, and change the route to use the address of the ISP router. Use the following commands to do this
no ip route 0.0.0.0 0.0.0.0 FastEthernet0/0
ip route 0.0.0.0 0.0.0.0 188.8.131.52
I also presume that there are not four class C subnets inside, but one subnet of 1018 addresses (plus subnet address and broadcast) ? Otherwise you will also need to add more routes for the inside subnets for it to work correctly.
I would also advise you remove the ‘ip http server’ command. If you haven’t done it already, lock down the access to prevent anyone else accessing the router and changing the configuration by adding an access-list and access-class to the vty ports.
Please post more information, if the change to the default route does not fix the issue.