Hold person is a spell which prevents the target from doing anything except attempting to escape the spell as a full round action on a failed save. Slow is a spell which denies targets some actions on their turn while under effect of the spell.
As it is stated in hold person that breaking free is a full round action, if they are slowed does this make it impossible to escape from hold person?
Hold Person
The subject becomes paralyzed and freezes in place. It is aware and breathes normally but cannot take any actions, even speech. Each round on its turn, the subject may attempt a new saving throw to end the effect. This is a full-round action that does not provoke attacks of opportunity. A winged creature who is paralyzed cannot flap its wings and falls. A swimmer can’t swim and may drown.
Slow
An affected creature moves and attacks at a drastically slowed rate. Creatures affected by this spell are staggered and can take only a single move action or standard action each turn, but not both (nor may it take full-round actions). Additionally, it takes a -1 penalty on attack rolls, AC, and Reflex saves. A slowed creature moves at half its normal speed (round down to the next 5-foot increment), which affects the creature’s jumping distance as normal for decreased speed.