Internet did work, now it won't

[#1]

My laptop connected no problem via a plus net router last night.  Today it won't.  Not wireless or ethernet.  Other laptops work fine (i'm here, aren't I?).  There are no problems on device manager (no red x on the broadcom wireless card or anywhere else), I have re-booted the laptop and the router, I have removed the network connection and put it back in again, checked all passwords etc, no good.  Automatic updaates on but none last night.
On network and sharing centre I get a yellow ! between my laptop and the router and a red X between the router and the internet.  Windows can't fix it.
Good signal strength
Access: "limited connectivity" but 192.168.1.1 doesn't find the router
Dell inspiron 1501, vista home premium.  Dead wireless card??  Is there an easy way to test it (the Insprion has no wireless switch or indicator lights)
Many thanks

[#2]

I assume from your opening statement that the laptop won't connect using a cable either.
Which security package do you have and have you tried disabling the firewall

[#3]

Hi northnewforest,
The yellow exclamation mark you can see in Network And Sharing Centre .  The issue is that your laptop is not being assigned an I.P. address from your router (by DHCP) and so this means that no data can pass between them.  To fix this there is a Microsoft article to follow here:
http://windows.microsoft.com/en-GB/windows-vista/Change-TCP-IP-settings
You should follow the options for "Internet Protocol Version 4 (TCP/IPv4)" and check the settings there.  Can you let us know whether this is configured to "Obtain an I.P. address automatically" or "Use the following I.P. address" ?  Also can you confirm the brand and model of the router you are using?

[#4]

Hi.  Thanks for your reply.
Router is a thompson tg585 v8 (supplied by plus)
Security:  Microsoft security essentials, windows firewall
TCP etc:  "obtain an IP address automatically"  "obtain DNS server address automatically" and on the alternate config. tab " automatic private ip address (these settings are the same as on the netbook I'm using to write this and which has no problems (yet?))
Thanks

[#5]

Does this find the router http://192.168.1.254

[#6]

@ northnewforest
I suggest you return to the "Internet Protocol Version 4 (TCP/IPv4)" settings page and switch to "use the following I.P. address" and enter the TCP/IP settings manually as below:
IP address: 192.168.1.100
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.254
Preferred DNS: 212.159.13.49
Alternative DNS: 212.159.13.50
And retry your connection.  This at least will ensure your computer is connected to your router correctly and you should then not see the yellow exclamation mark.

[#7]

"internet explorer cannot display the webpage".....etc

[#8]

OK...changing the ip adress seetings and we now have NO yellow !  but we have "unidentified network" instead of the "plusnetwireless..." that it should be, a red X between that & the internet.  Progress but no cigar yet    a reboot didn't improve it further

[#9]

I just turned the firewall off -  still no internet.  Curiously the "network location" shows up as public network" rather than "home" as originally set.  Any way to change this back?

[#10]

Just changed the location from public to private: still no internet

[#11]

Can you try both a ping and traceroot to www.plus.net and post the results?
You will need to open a command prompt and type:
ping www.plus.net
and:
tracert www.plus.net
respectively.

[#12]

"ping request could not find host www.plus.net. ; Please check the name and try again.
and
"unable to resolve target system name www.plus.net"

[#13]

Have we clearly established whether we are dealing with a with a wired connection or a wireless connection or both?  Have we clearly established that when nothnewforest set a fixed IP and DNS this was done on the network adaptor actually being use, or both?  Can we even ping the router?

[#14]

In the original post it was documented failing via wired or wireless.
Since the yellow exclamation mark indicating a TCP/IP problem disappeared when entering the connection details manually it would be safe to assume that the correct adapter was adjusted.
I agree however that the next step is to try and ping the router:
ping 192.168.1.254
and then try to ping:
ping 212.159.8.2
Let us know the results.

[#15]

neither work, currently on wireless
fixed ip set on the duffer, not this one (if it ain't broke etc)
ping 192.168.1.254 destination host unreachable
ping 192.168.1.100 that worked (I know you didn't ask for it but...)
ping 212.159.8.2 destination host unreachable