So I just built this great computer, and I have an old computer(ok, not old, just not as fast, its only about 6 months old) and I'm going to take out the hard drive after backing it up and I'd like to put it in my new one.
Heres the thing though:
The old one has XP on it and this one has vista. I'm not going to use xp anymore, but I was wondering if its pretty easy to add a hard drive WITHOUT screwing up this new computer? I mean, after I've formatted it. And this computer is set up SATA connected, but the other hard drive is IDE connected. Would that be a problem when adding it? OR should I just say screw it and deal with a 160GB hard drive? Let me know.

it's not generally a good idea to mix ide and sata (i've heard anyway, i'm still on ide ) but it would be ok putting in a slave drive with xp on into a vista machine. my slave drive had xp on but because it's a slave drive it doesn't really matter what's on it

Well I got to disagree I use both IDE (Ultra 133) and SATA 150 together it works. The OS was setup by me on IDE Ultra then SATA 150 storages all the network system docs. No real problems actually none..

Now if the Primary is SATA and you want to put IDE HDD on the Secondary IDE channel you can. Make is a slave and your CD/DVD Recorder should be the Master on the Secondary IDE channel.

so leave the sata as primary but put the ide on the secondary channel, but as slave and have dvdrw as the master on the secondary channel? just making sure so that I don't kill something in my computer doing it...

and if i do that, is vista going to give me trouble about an extra hard drive suddenly being there?

It's the BIOS you need to be concerned about, not Vista.

So long as the BIOS settings match the drive you install, it should work OK. When BIOS starts, it initializes the hardware, performs POST and then eventually reads the Master Boot Record of the master drive. You'll be setting your new drive with Vista, so BIOS will boot to your Vista installation and that's it! Vista will see and access the other hard drive, provided it's setup correctly in BIOS. But it won't detect the other XP installation.