Matlab doesn't recognize processors.

I have windows xp(x32) and 2 processors Intel Pentium 4 3,20 GHz.

I set "parallel/manage cluster profile/number of workers =2" , run "validate"and test is OK.

I edit:

    feature('numCores');  % local processors

1

getenv('NUMBER_OF_PROCESSORS')  %windows processors

2

If I run "matlabpool" it tell me:

>> matlabpool
Starting matlabpool using the 'local' profile ... connected to 2 workers.
>>

but

feature('numCores');

always return 1.

Can someone tell me why?