your new main computer can multibox by itself. if you got a better 30" monitor you could put all 5 toons on that one screen. but as it is now i think have a main screen that big will really hurt you when trying to keep track of what your other toons are doing because they will be out of your vision, unless you put the screens about 5 feet away from you.

I would recommend getting 2 good 24" screens for the money. put your main on one screen and the other 4 on the other screen. if multi boxing is for you and you find that the 1 computer set up is not working for you and want to add more comps than it will be easy enough.

if you really need to run a 32 bit operating system because of some programs than partition your hard drive with 2 different versions of vista. one with vista 64, which will be able to use the 4+ gig of ram you will need to multibox, and the other with vista 32 or windows xp.

5 comp multiboxing is really not for someone that is don't a serious computer geek, like you say you are not. there is a lot more to it, you have to link all 5 computers, which may sound easy, but read some guides from people who have and you may realize it is not for you. save yourself the time and aggro and software mutlibox using 1 machine. change your monitor setup and partition your harddrive or add a second drive that you can boot in 32 bit windows.