Firstly, many thanks for reading and, secondly, I hope you can help.
I am really frustrated with my wifi connection and I am sure you might be able to help.
Connection
NTL 4Mb
NTL 250 Cable Modem
Netgear WGR614V3
2 Laptops (Dell XPS Gen 2, HP (something))
1 Network Printer (HP Photosmart 2575)
Speed Test
73ms
D: 3947kpbs
U: 381
http://www.speedtest.net/
Set-up
Netgear wired to NTL 250
Currently IP and DNS assigned automatically.  Default MAC address used. All firewalls off.
Printer ethernet
Dell mixed (static route set-up)
HP (something) mainly wireless
(don't know if this helps - Netgear)
UPNP - On
RIP - On
DHCP - On
Background
I used to use the same router through the set-top box about 1.5years ago and it was fine.  Now I am using it through the NTL 250 cable modem and its not!
Initially, the connection WAS very slow (127kbps).  After researching, I turned off all the firewalls and things picked up considerably. I used static routes (?) by assigning IP address and DNS manually.
I use the Dell laptop (so this is my base for the problems). 
Problems
1. When using the Dell wirelessly, the connection works well for about 30-60 mins and then drops.  Repairing or disabling/enabling does not resolve the issue and I need to reset the router and modem.  Sometimes the laptop fails to connect to the router and other times the router connection is fine.
2. For prolonged use, I need to use the ethernet connection.  This can't just be plugged in and often requires a hardware reset (of the modem + router)
3. It would appear that when the HP is being used, if I power up the Dell, then the connection is lost for both of us.
4. I have tried various combinations of static / assigned IP, DNS, etc.  DHCP on and off (yeah, I know but I was new to this). 
Desired Outcome
I just want it to work.  To be able to use both laptops and not have to reset the router/modem 3-4 times a day
I am sure this is all human error, but I just don't know what else to try.  It's driving me mad having to always be in the living room.  I have called NTL and they were... well... probably as helpful as they could be.
Can anyone help?  I would really appreciate pointing in the right direction.  (please let me know if you need more info)
Thanks