How much hp do i need to survive zak?

well, as stated above, i will have to be able to survive WITHOUT HB as they will not be providing me with a buyer party and because of that, i will be getting a free helm....crap i have vista + laptop but i've survived zak once before on my cb....hopefully i don't dc haha

I don't see what using a laptop has anything to do with not being able to survive Zakum. I preferred my laptop to my desktop (until I upgraded it's video card) because I could go and chill on my bed.
Visa on the other hand, would make a difference.

Anyway, you should be fine as long as you have max magic guard. Most Zakum will hit you for would be 2,800-3,000 (depends on your defense), and with magic guard, your MP will take most of the hit. Just bring about 500 Power Elixirs (I don't know how long your friends runs are. KoM's generally are 15 minutes, and that's what we recommend for our runs. So, give or take.

Hope that helped.