HELP with agarose gel

[m]

I am having troubles running simple digests (3.5kb plasmid and 1kb insert)
on a 1% LMP and regular agarose gel. The problem is that DNA is not
entering the gel.  I have been denaturing the DNA (10' boiling) prior to
loading the DNA into the wells.  My molecular wieght standards run fine on
the gel, so I am fairly confident that my gel and buffers are O.K.  On one
occasion I had duplicate digests (treated exactly the same), one sample
ran fine, the other failed to enter the gel.  If anyone has any
suggestions please drop me an E-mail: tkuwada at neuron.uchc.edu.  Thanks in
advance.

Tim Kuwada
tkuwada at neuron.uchc.edu