2005 Camry V6

I had to replace battery about 2 weeks ago. Went
to dealer and bought battery from them. Have
driven car, no problem until the other day. Got
home from work, then had to go to store and
nothing, no clicks or anything.  Lights, radio all
work. Battery cables tight.  Trying to find starter
relay switch and replace first before trying to
remove starter. Where is it located.  I do not see
anything in the long black fuse box next to the
battery.