After a period of time my laptop will lose its ability to connect to the internet even though it is still physically connected to the LAN. It has take a while to work out the problem but finally I have an answer.

Byte Mobile is the dicky compression software peddled by Voda. When you install the software for one of their data cards it adds a DLL called bmnet.dll to the LSP (layered Service Provider). Apparently after removing the Voda software it can cause a break in the TCP/IP handler by leaving an entry for bmnet.dll in the registry.

I found the offending entry by using HijackThis.

Luckily there is a tool to remove it and this is a known issue.

LSP Fixer