Problem using solve... keeps busy

Hello.

I am trying to solve
[ys] = solve('L-1/2/(x^2-2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^
(1/2)*(-2*y+2*ys)+1/4*(K-1/2/(x^2-2*x*a+a^2+y^2-
2*y*ys+ys^2+z^2)^(1/2)*(-2*x+2*a))/((1/4/(x^2-2*x*a+a^2+y^2-
2*y*ys+ys^2+z^2)^(3/2)*(-2*x+2*a)^2-1/(x^2-2*x*a+a^2+y^2-
2*y*ys+ys^2+z^2)^(1/2))^2)^(1/2)/(x^2-2*x*a+a^2+y^2-
2*y*ys+ys^2+z^2)^(3/2)*(-2*x+2*a)*(-2*y+2*ys)-1/2*(K-1/2/
(x^2-2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^(1/2)*(-2*x+2*a))^2/
((1/4/(x^2-2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^(3/2)*(-2*x+2*a)
^2-1/(x^2-2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^(1/2))^2)^(3/2)*
(1/4/(x^2-2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^(3/2)*(-2*x+2*a)^2-
1/(x^2-2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^(1/2))*(-3/8/(x^2-
2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^(5/2)*(-2*x+2*a)^2*(-
2*y+2*ys)+1/2/(x^2-2*x*a+a^2+y^2-2*y*ys+ys^2+z^2)^(3/2)*(-
2*y+2*ys))=0','ys')
with no result.

The pc is kept busy for hours.
Any ideas? Is it that complex, or solve can't find a
solution?
.