he needs a computer NOW?
This is what you need:
RAM - ddr3 is best. Speed/brand doesn't matter.
CPU - probably have to buy this one, get the cheapest sandy bridge.
PSU - anything above 400W will be overkill. Does not matter much right now. The difference between a shitty PSU that works for 10 years and a good PSU is zero. Check the
archive for reviews when he upgrades, as there's no telling when a shitty PSU is going to blow. It's also probably not worth buying a shitty PSU unless it's dirt cheap. Find a good one for cheap instead (loan him money if need be).
Motherboard - cheapest thing that goes with your cpu. probably have to buy this one.
graphics - intel onboard sucks. AMD's onboard is great, but requires an FM1 socket, which I can't see being upgradable in the future, and is hell of expensive. You buy AMD's onboard for the long haul, not for an upgrade path. Get whatever you can scrounge up. The 6670, 6770, GTX 460 (both versions), GTX 550, 7750, 6850, 6870, GTX 560 are the best price/performance, in pretty much that order.
heirarchy chart for graphics.
Case is optional. use a screwdriver to turn on the computer (short out the power on pins).
HDD is free. You might be able to take out the HDD if it's sata, but you can also use a thumb drive as your HDD, so no worries there.
Optical drive makes life easier, but you should probably skip it unless you can get it for free.
"Parliamentary inquiry, Mr. Chairman - do we have to call the Gentleman a gentleman if he's not one?"