Leave the power supply to your computer plugged in but turned off(I think US outlets have switches on them at least most do). That will leave any metal on your computer at earth potential, just touch a metal part before doing your work.I usually keep at least one finger on metal at all times. But I'm paranoid and have worked in some places(eg Fisher Library in Sydney, which is copper sheathed and in which the static electricity is ridiculous).If you just touch the metal first you'll be fine.