NAT issues DLINK DSL-2640B Xbox live

[#1]

Hi there.
Just wondering if anyone would be able to help me out at all. I'm not very technical so if you ask me something I may need an explanation on how to do it
I have the dsl-2640b router, and we have had a problem lately with the NAT, noticeably on xbox live. It used to be open, but for the last month or so its been moderate and occasionally strict, and my fiancé often has trouble joining friends games etc.
Is there anyway we can get it back to open? Thanks

[#2]

Hi missisbeki,
Have a look at the 2640b manual. This has some instructions that may help you.
Jojo

[#3]

Thank I have had a look through but, menus and everything are totally different to the ones I get when I log onto my router 
So I'm still a bit stuck, plus a lot of what it wanted me to do baffled me 

[#4]

Sorry I'm not overly familiar with that router.

[#5]

No worries, apparently it is a bit of an oldie, I rang up for support before and it took me to my 4th CSA who knew how to work that router.
Thank you for your help anyway, hopefully someone will be a long shortly who deals with oldies 

[#6]

Just thought I would update. We managed to get it working again.
All we had to do was re-test the connection via the xbox network settings and it sort of reset the connection between the router and the xbox, and it was open again 
Pretty easy fix so at least we know for next time now.