Helpless


 * Paralyzed, held, bound, sleeping, unconscious, or otherwise completely at an opponent’s mercy. A helpless target is treated as having a Dexterity of 0 (-5 modifier). Melee attacks against a helpless target are automatic critical hits. You can always hit a helpless creature unless you roll a 1 on your attack roll. -- from the in-game glossary

A PC or NPC is helpless when it is asleep, held, mesmerized, prone or has its strength reduced to zero. No action can be taken, objects cannot be interacted with (not even rest shrines or chests), and inventory items cannot be moved, traded, equiped or consumed.

Often this is caused by a spell such as Hold Person or Sleep.

All attacks against a helpless opponent are critical hits (although they may be treated as normal hits in the case of fortification).

When your strength is reduced to zero, you have only a few options:
 * If this is only temporary (e.g. when hit by a Ray of enfeeblement spell), you may wait for it to wear off
 * Tavern regeneration restores strength
 * The Cleric Lesser restoration spell (available as wands) restores strength one point at a time, and there may also be higher-level cleric spells (most likey the Restoration spell) giving full restoration
 * Bull's strength can also be cast on you, in order to get a temporary +4 to strength
 * Someone should check whether dying helps or not