I am interested in ways to achieve bulletproof reversible disabling of internet connection. E.g. I figure that if I just run "ipconfig /release" the smart trojan could reenable connection by doing the equivalent of "ipconfig /renew" via appropriate Windows api. Perhaps other programmatic methods of turning off connection could be defeated similarly by the trojan.
So would corrupting some underlying Windows dll work? First of all, is it even possible, without booting under Linux? Second, if it is possible, what dll would be a good target to mess up to get rid of networking while not affecting other essential Windows functionality?
ETA: thanks for the responses. I don't want to discuss the disabling the adapter approach because... because this question is not about that and because if I can programmatically enable/disable something, then so can the trojan. The idea with removing network connectivity is not doable because there is no physical way to shut off wifi adapter in my machine.
Downthread uSlackr said that Windows "will fix any system file". So, how would it fix it? Does it have backups in some identifiable location that could also be corrupted?
Are there other problems with the feasibility of this approach, other than Windows restoring the files?
ETA2: on second thought, would the wifi adapter's driver file, as opposed to the dlls of Windows itself, be a more convenient target?