This should be easy for you guys

I have three problems with my router.
1 is that the wireless(sometimes wired) computers will momentarily be disconnected from the internet and then reconnect (this is annoying)
2 is that when i play xbox, i cant play with people because my NAT is either STRICT or MODERATE i have gotten it to OPEN before but the router changes it to STRICT or MODERATE.(On its own) when i change this i go to ENABLE the UPnp within my router setting, Once enabled my NAT should be OPEN, but it is MODERATE.
3 my sister's computer and her friend's wireless computer cant contact the router network.

I am using a RANGEMAX NEXT WIRELESS-N ROUTER GIGABIT EDITION
WNR854T, with the newest firmware on it.

I will do my best with a network mapp)

Internet-
Motarola modem-
Rangemax router
(Wired)My computer [win 7]
(Wired)brothers computer [win vista]
(Wired)Internet TV
(Wireless)Dads laptop [win 7]
(Wireless)sisters computer [Win vista]
(Wireless)Sisters Friend Computer [vista]
(Wired)Motorolla Vonage Router TO
{(Wired)Internet Phone}
{(Wired)DADS computer [Win 7]}

Everything is generally new so i can't really see anything being outdated,but you never know.and my dads wireless laptop is literally 1 meter away from the router so it cant be a range problem and my sister and her friend were able to connect to the inter net with 2or3 of 5 bars (signal strength). This router my dad bought was refurbished and did work fine before(for a little bit). when i go to set up the router i have to use the my dads laptop to configure the router and when the router saves the changes i've made it is momentarily disconnected with the router than reconnected (just a little extra knowledge).Thanks for any suggestions you may have.

 

First you have to find out whether the disconnection is the Internet per-se or actually the computer loses its connection to the Router.

What is the model number of your Modem. I.e. make sure that it is Not a Modem/Router Combo.

It is also possible that if your Internet connection is relatively low (like 3 Mb/sec. or less), and there is so many computers using it at the same time causing fluctuation in Bandwidth.

Instability can be also caused if users are busy with heavy download (Like the typical p2p).

 

The model of my modem is a motorolla surfboard model: SB5100 and my DAD says it is strictly a modem.

also when i get disconnected from the internet, i trouble shoot my connection and it says that the "default gateway was not available" that fixes it for about 5-15 minutes until it happens again then i run the same procedure. . .

We use network magic pro. and when i test the DL speed i get about 10MB but when i test the upload speed i get 0MB (same result with 2 different pc's)

I'm actually starting to wonder about the modem itself cause i looked at a forum regarding the modem and people were saying that the modem doesn't like handling the ip addresses of lots of computer (we have 9)rolleyes

 

also it says my modem's LAN ports type is 10/100 Base-TX (RJ-45) and my routers (1 LAN + 4 Gigabit Ethernet LAN Ports so 10/100/1000, would this affect anything? does this mean i should get a newer better modem that supports a LAN 1000? the router looks fairly new where the modem is 3-4 years old (do you think it could be outdated or obsolete?)

if your interested here is where i found information regarding my modem and router. . .
Modem
http://www.speedguide.net/broadband-view.php?hw=6
Router
http://www.netgear.com/Products/RoutersandGateways/RangeMaxWirelessNRoutersandGateways/WNR854T.aspx

 

NVM we fixed it