[leopold]

The wrist strap isn't essential.

To be on the safe side it may be worth earthing yourself first, by touching a radiatior or space heater - or anything metal that is likely to be earthed.

One other tip - you can follow this even though I always forget! Make sure the IDE ribbon cables are still connected to the drives and motherboard before you put the case back together. I always manage to loosen one of them somewhere and lose drives...