Thanks for the info Somebody Some of it's a bit too advanced for my limited tech knowledge.

The laptop has onboard wifi, which started dropping out soon after I bought it, so I bought a Belkin USB wifi adapter, but isn't really any better. 9/10 times if I run the wifi troubleshooter, it eventually resets the network adapter connections and that cures it. Sometimes I hibernate the laptop for a couple of minutes and that fixes it too. I've also found that running CCleaner and cleaning up a couple of hundred megs of junk has cured it, but that may just be coincedence? From time to time the trouble shooter says the DNS server couldn't be found, or the link to the router is broken. If this happens I turn the router off for 10 seconds, re-boot it and reboot the laptop at the same time and that also fixes it.

I don't run much software in the background, I usually keep Googletalk open, MS Outlook, and maybe a couple of IE9 pages are open at the same time. However, a lot of programmes automatically update themselves in the background (Flashplayer, Adobe Reader, Windows..etc to think of a few).

It is very intermittent, somedays it will drop out at least a dozen times and other times it can go 2 or 3 days without a problem (today has been fine).