You didn't say what OS you got but at own risk you might try this; [if on xp, create a Restore point first] You can also do registry backup on W98 but I forgot how..]
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Can't download anything from the internet:
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Go to Start
Run
Type
regedit
when the regedit window opens
Navigate to this key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\ Plugins\Extension
Careful here, there might be a key named Extension(s), do not get the two confused.
Right click on Extension and choose delete from the menu
That's it apparently. according to;
http://www.rselby.com/Troubleshoot.html#xp40