Desktop

Most likely, there is a IRQ conflict between devices.

Try moving plug-in cards to different slots.

If there are any ISA cards in the PC, make sure that the jumpered IRQ matches the one the motherboard assigns to the slot.

Chas

If it unlocks (or even if it does not) after several minutes, you could check settings -> control panel -> system -> device manager for any yellow ! or ? to see what card may be causing the problem/conflict. Reseating the cards may give a better connection, PC could have been bumped enough to cause a poor connection to an improperly seated card.