So you've got some spyware, ad-ware, or viruses on your system. For whatever reason, you are unable to get ahold of a virus detection & removal program, or a good ad-ware scanner. Maybe this certain infection has disconnected you from the Internet. Such viruses do exist.

There are some temporary solutions to infections & infestations that you can exploit. For starters, try hitting start, then run, and type in MSCONFIG. This will bring up a screen that displays what processes are executed upon starting up your PC.

Hit the startup tab. These are all the processes that will start when you start your PC. Try hitting disable all, this will turn off all processes that startup with your PC (it will also make your PC load a lot faster). Although many viruses and infections are liable to re-enable themselves, this tactic usually works as a temporary solution until you are able to get something on your PC to clean the infection (for more information on cleaning up infections and infestations, please refer to my article on "What to do once you are infected with spyware, ad-ware or viruses.)

Also, you could try running your PC in safe mode. In safe mode, many startup features are disabled. If you are having troubles connecting to the Internet in normal startup mode, safe mode may work for you. This will give you the required time to download a virus scanner and clean up your infection.