most likely theres a program blocking you to access the internet intermittently... heres what you can do

 

1. check for EMI/RFI near your modem and move it away.. ex. flourescent lamps or speakers

 

or

 

2. go to safemode w/networking try to surf there and see if theres any changes at all.. if it all goes well then you can conclude that there a program conflicting on your system... that should be removed or disabled...

 

or

 

3. go back to normal mode and open cmd prompt type this commands netsh int ip reset filename.txt and netsh winsock reset then restart your pc...

 

do that using hardwired connection first if it all goes well then you can use wireless connection afterwards...

Thanks but no joy. have tried all suggested solutions twice. Moved phone point, moved laptop around, done cmd stuff, removed all added programmes ... in safe mode with networking would not allow any connection to internet, wired or unwired - any significance? Tried this before and after removing software (surely up-to-date Office and Norton apps can't cause problem?).

 

Any more suggestions other than installing XP?

---

@Malarki wrote:

Thanks but no joy. have tried all suggested solutions twice. Moved phone point, moved laptop around, done cmd stuff, removed all added programmes ... in safe mode with networking would not allow any connection to internet, wired or unwired - any significance? Tried this before and after removing software (surely up-to-date Office and Norton apps can't cause problem?).

 

Any more suggestions other than installing XP?

---

did you try to ping a particular website... like yahoo.com if you see destination unreachable or unknown host then you might have a problem with firewall or your ISP... coz you mentioned you cant even access internet even hard wired w/c suppose to be not an issue since you mentioned above that you can access internet using hard wired.... try to ping also your router/modem just to check if its a firewall issue...

It's letting me ping the router and most websites - but not all (notably not my online bank) - without any loss.

 

Feels like sometime is blocking wireless access to most sites just on this connection with the Zyxel - but all a bit random.  Can access www.chairkickers.com, www.barbican.org.uk, bbc, google and microsoft sites but not www.organicdelivery.co.uk, www.co-operativebank.co.uk, www.facebook.com and many others.  But all accessible via next doors unsecured wireless network.

 

?????? 

Right looks like it's an issue of compatibility with routers WPA encryption - have switched off encryption and just running WEP.  Everything now works.  Not as secure as I'd like though - going to contact Zyxel about it and see if they've a solution.

 

Thanks for your time kitomatsing. 

your welcome.... cheers mate :)