Try the following:
- Rename the blind comp something diffrent, like TEMP.
- Ping the router.
- Can you get on the internet w/ that machine? What kind of connection are you using? Cable, DSL, dial=up, what?
- Check the cable
- Check the little light on the router to see if the router sees the machine
- Use Ctrl-Alt-Del to close all tasks but systray and explorer
- If that worked, Restart and close all tasks but those two and something else. Then if that worked, try w/ the 3 tasks and an extra task. Repeat until failure.