your question doesn't really make any sense. death certificates have to be paid for and signed by a registrar, every death registered since 1837 could not possibly be available online.
you can look in the gro index for deaths to identify the correct entry and then order the certificate online to be delivered to your home address.
http://www.gro.gov.uk...tificates/default.asp
if you do not have access to the gro index i could look for you.
or the other possibility is that you are saying you cannot find the death in the gro index, in which case you need to give more info to enable other options.