MacBook network diagnostics problem - Internet FAILED Server FAILED

Dear all

I wonder if someone could please assist in the problems I am experiencing with my 2009 2.13 Intel Core 2 Duo MacBook which is on 10.6.8.

The MacBook has been working flawlessly for the past 4 years.

72 hours ago it refused to provide internet access via my airport wi-fi point. Interestingly, my G5 iMac (which I am typing on now), G4 iBook, iPhone 3GS and 4S and iPad all continue to access the internet through the airport no problem.

Going through network diagnostics the following are all green network status: airport; airport settings; network settings; and ISP. The following are at red network status: internet and server (these both say failed).

So I have tried connecting the ethernet cable direct from my modem to MacBook. Going through network diagnostics the following are all green network status: ethernet; network settings; and ISP. The following are at red network status: internet and server (these both say failed).

I am finding great difficulty in tracing the problem and fixing.

I have tried all of the following (none of which have got me back online):

• reinstalling 10.6.8 (downloaded via iMac onto a memory stick);
• reset PRAM;
• hard reset of airport express;
• adding and then deleting aiporrt and ethernet settings in System Preferences, Network;
• Renewing DHCP lease (which seems to work anyway);
• Checking the DNS settings;
• Comparing iMac (which works OK) settings with MacBook (nothing looks different);
• Running through Network Diagnostics to try and fix the problem;
• Deleting various files in Library, Preferences (as per recommended fixes following Google search).

I am struggling!

Some things to note which may/may not be of relevance:

• battery health fluctuates between 80-88% and has done 949 cycles (original battery and probably needs replacing);
• recently experienced date/time issues which did not allow internet access, had to set date/time manually, regained internet access and then set date/time automatically via Apple Europe; and
• No other third party/dodgy software installed.

My preference is not to re-install OS X from the start as I do not want to wipe the hard drive - and this does not guarantee to be a fix.

If you have read this far thank you very much - if you can offer a fix I would be pleased to hear from you.

In the 10 years of buying Apple products this has only been the first major hicup - but it is starting to annoy me now!

Many thanks and best regards.