Try contacting the ISP in question
for a fix. Some ISP's have an UnlockIE file on their CD.
Failing this, there is a registry
hack that you can try. Go to START / RUN and type 'regedit'. Navigate
your way to:
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet
Explorer\Control Panel
You should be able to stop the block
by either deleting the home page key or by setting its value to zero.