Wireless connection suddenly failed - XP

[#1]

A laptop running XP SP3 which was happily connected to the internet via a Netgear DG834G wireless connection suddenly wouldn't get an ip address automatically. Signal strength is excellent.
After a lot of messing about we fixed it by putting an IP address and DNS servers directly into TCP/IP properties.
Previous I had tried the commands netsh winsock reset catalog and netsh int ip reset reset.log with no effect.
The ipconfig/all command showed a completely rubbish ip address.
Any suggestions as to why this happened. Note that disabling the firewall had no effect

[#2]

Are you on the ADSL2+ test?
My Netgear DG834GT happily connected to the internet - but wireless became a question of luck.
I was mostly using static addresses too.
I have a new Plusnet router now - which has it's faults, but not the ones described by you.

[#3]

No - still on the old tried and trusted system
Note that another computer connected via wireless without a problem so I think the problem is with the laptop/XP

[#4]

Second computer wouldn't connect this morning - router reboot fixed it
Still don't know what caused it but will see if it happen again

[#5]

I would make a note of the configuration - in case you return your router to factory settings.

[#6]

That isn't a problem - I have changed routers so often when trying to solve a problem that I know them by heart 

[#7]

sounds to me like your routing tables gotten fried at some point.  If you are still using manual IP for the Lappy put it back on auto and run a ROUTE PRINT and hve a look see what the Active Tables are saying (although you probably done that already).

[#8]

You need to isolate the problem and see if its windows not getting a ip hence a fault with windows stack or if the router dhcp is not working.
Download
http://www.softcab.com/dhcp-server/index.php
A mini dhcp server and run that for a few days setting it to the right ip range for your router(disable the dhcp on the router). If you can get a ip from that ok then it will show the problem is with the router. XP if it cant get and ip uses its own built in default rubbish ip