Go into Internet Explorer.
Type this, into address bar: 192.168.1.1
User name: Admin
Password: Admin (if admin doesn't work, use password)
OK, to look for UPnP, it would be in "Advanced".
Click, or Look under. (for, NTGEAR is different, advanced isn't clickable, It's just under advanced)
OK, UPnP, SHOULD be there.
If it is, Click it.
And simply Click "Enable". Theres something else. Theres an option, to randomize ports. DON'T USE THAT ONE.