Is there any way which I can update without an internet connection? Thanks.
Update without an internet connection
There is a way. It is possible to copy the bases.cav (in the scanners folder) of another computer to yours. To do so you need to temporarily disable Defense + on your computer. That is done quickest by clicking on the systray and adjusting the Defense + Security Level to disabled.
Remember to enable Defense + again because Comodo will not alert after 15 minutes or so.
When the above does not work booting Windows in Safe Mode always works.