What do you do if you think you are owed a claim on life insurance but
you do not know the name of the insurer? How do you determine the name
of the carrier that actually insured you?

I would ask a few questions first.  Who purchased this policy?  You or
someone else?  If it was someone else I would ask them.  Was it a
policy thru work or a personal one?  If it was thru work, even a
former employer, their employee benefits department might be able to
help.  I imagine payments were made.  Can you look at your check
register to see what payments might have been made?  Did you get it
thru an insurance agent?  If you know who that was, he could probably
figure it out.  Have you looked thru the house or safety deposit box
for copies of insurance policies?  Sometimes this sort of thing gets
tossed in a drawer or box and forgotten for years.

Twenty years ago my friend?s father died. The mother, in particular
knew that the husband had a substantial life insurance policy on his
life. However, the mother knew nothing more than that. Due to
ineptness, nothing was ever done to try to collect on the policy. At
the time of the husband's death, no one in the family knew the policy
number or the amount of the policy or the carrier. Since 20 years have
gone by, there is no knowledge of who wrote the policy etc. Therefore,
the question is, is there anyway to find the carrier of a policy when
no information is available?

As an example, do insurance companies have a centralized database so
that you can call into a central office to determine if their records
show that they have a policy on the xyz individual?

These articles might be helpful.

How to find lost life insurance policies
http://moneycentral.msn.com/content/Insurance/Insureyourlife/P35421.asp

Life Insurance Policy Search Louisiana
http://www.ldi.state.la.us/LifeAnnuity/life_annuity.htm

Tracing Missing or Old Life Insurance Policies - Texas
http://www.tdi.state.tx.us/commish/columns/cc1100.html

Missing Life Insurance Policies
http://www.virtualchase.com/howto/life_insurance.html

Unclaimed Life Insurance Policy Search  
http://www.unclaimed.com/unclaimed_life_insurance.htm