THREAD_PRIORITY_HIGHEST         -1
THREAD_PRIORITY_ABOVE_NORMAL    null
THREAD_PRIORITY_NORMAL          -2
THREAD_PRIORITY_BELOW_NORMAL    1
THREAD_PRIORITY_IDLE            2147483647
THREAD_PRIORITY_LOWEST          -15

##</code><code>##

Description   Process priority  Thread Priority
Realtime          256              15
High              128               2
Above normal    32768               1
Normal             32               0
Below normal    16384              -1
Idle               64              -2
Lowest            n/a             -15

##</code><code>##

$returncode=Win32::Process::Open($obj,$pid,0);
print "\n $returncode \n";
$returncode=$obj->SetPriorityClass(THREAD_PRIORITY_LOWEST);
print "\n $returncode \n";

##</code><code>##

$returncode=$obj->SetPriorityClass(32);