Are you saying that you accidentally clicked the
Network tab in
System Spec and now it is giving you the error message? If it is so, then I am sorry to say but you are having a lot of fishy problems. It would be easier and much more time saving to perform a complete reinstall.
To do so, you might find the following article useful.
How to Downgrade Windows Vista to XP
I don't normally recommend this solution but the problems you are facing are very severe. It would be more sensible to perform a complete reinstall.
Sorry I couldn't be of more help. Let us know if you want to choose that path.
-- Goku