If possible, I would remove the Netgear WNDR3400 from your setup and replace it with the Cisco RV100W. There should be no need for the Netgear (unless I'm missing something) and by adding this router you're confusing your setup.
It sounds like you connected a LAN port on the Cisco to a LAN port on the Netgear. The default address for the Cisco is probably 192.168.1.1. Either there's an IP address conflict, or you're on a different subnet (192.168.0.0) than your Cisco router, and now it is acting as a switch only.
If you want to keep both routers, I would still use the Cisco router as your "main" router and simply connect a LAN port on the Netgear to a LAN port on the Cisco.
First though, we're going to have to isolate this setup.
Remove the Cisco from the rest of your network
Plug your computer in to a LAN port on the Cisco. Don't plug in anything else. Now open a command prompt (Win+R to open run box. Type
cmd. Push enter.) Type the command
ipconfig /release then
ipconfig /renew. What this will do is release the address you received from DHCP earlier (likely coming from the Netgear router) and pick up an appropriate address from the Cisco router.
Configure the Cisco router
Try the default address
192.168.1.1 in your browser and see if it pulls up the page. If it doesn't, run the command
ipconfig and figure out what the default gateway is, then input that.
You're kind of on your with the VPN configuration. I believe this is the manual you need.
Turn off DHCP on the Netgear
Now we need to configure the Netgear router so that it isn't serving DHCP (we don't want DHCP on the network twice...) Connect your PC to a LAN port on the Netgear, then /release and /renew (same as above.)
Now hop on your Netgear's configuration page and turn off DHCP. Take a look in the manual if you can't find it.
Give the Netgear a staic IP
Crack open the manual again and figure out how to give the Netgear a static IP address. We're not interested in the Internet settings or WAN port. We're trying to give it a static IP on the private network side.
Remember your Cisco's configuration page address? We need to give the Netgear an IP address in that subnet. If the address was
192.168.1.10 should work depending on the DHCP range the Cisco router is using.
Set up the network
Plug your computer and the Netgear in to the LAN ports of the Cisco. Connect the WAN port of the Cisco to the modem. Do another /release /renew. Now reboot all network devices! Ping around and see if everything is working, and you should be good to go.