central processing unit - Load Average cpu linux server

i have a problem with the load average on server,
I'm using on server
When I check the processor - with "top" command
I see that :

top - 04:27:37 up 39 min,  1 user,  load average: 0.78, 0.77, 0.77

Tasks: 190 total,   1 running, 188 sleeping,   0 stopped,   1 zombie
Cpu(s):  0.3%us,  0.1%sy,  0.0%ni, 99.6%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   7136868k total,  1504092k used,  5632776k free,    52552k buffers
Swap:        0k total,        0k used,        0k free,   602524k cached

it's the same all the time..
cpu not working but load average is high!
why?
Where load average was taken?

thanks