I'm about to switch a HDD in my brother's computer to a larger one, but I'm not sure if I have to do something before doing so. The HDD I'm going to take out is still connected via IDE, but the new one is, of course, SATA. While I know installing SATA is a piece of cake (I've done it several times before), I don't know if I have to tamper with BIOS before taking out an IDE drive (because, as I recall, they had to be configured to be primary/secondary masters/slaves and I don't know if I can just leave it as it is or not) or if I have to do any other preliminary actions.
So, should I just take out the IDE drive and put in the SATA one, or will I have to do something before that?

Turn off the computer. Unplug IDE drive. Plug in SATA drive.

You're done. :)

You don't have to do anything with the bios regarding the IDE drives. Just unplug it and you're good to go. Hell you can keep it in there if you want, it won't change anything.

If the IDE drive is the boot drive, however, that's another problem...

Is there a particular reason for removing the old HDD at all? Why not just leave it in, and use it for extra storage?

@Foxhack
I *think* it is the boot drive. I can't reasonably squeeze one more HDD into that house, not enough space for it.

Unless the BIOS is really old or really unusual, it shouldn't be a problem anyway.

My brother will have a fresh install of Windows anyway, and he's backed up everything on that drive worth backing up, so no files need to be moved... or do you mean some other, normally non-accessible data?

He'll have to install the OS (Windows I'd guess), then probaby install whatever applications he use and maybe move his data over in some way (if he doesn't already store it on a separate drive - using a secondary drive or an external enclosure for the old drive).

Yeah, he's already backed up everything he needs from that drive on an other HDD, so it won't be a problem.
I was mainly concerned about the primary/secondary slave/master settings in BIOS.

If there is such data, eg. e-mail downloaded through a client (Outlook, Thunderbird, ...) and no longer stored on the server (a tip: switch mail provider if they don't provide enough storage or they automatically delete it after a while), browser bookmarks, and other stuff stored in "hidden" folders (may include savegames, depending on the game).

Nah, all such things are done (but he doesn't use a mail client anyway, and he uses a portable browser), I just thought there might be some meta-data stored physically on the drive which I can't copy normally.

Thanks for your responses, everyone, we'll try to do the HDD switch tomorrow.

I cloned my old hard drive to a new partition but it was a pain in the ass I don't want to go through ever again.

And it's often a better choice to start anew rather than bringing any (possible) software-related problems to the new disk (unless you're certain that the old installation is in a good shape), then move over documents and other files manually.
I suspected as much, this is often the case, just making sure you're aware.

Personally I prefer a real mail client (with IMAP connection and server storage, thankyouverymuch, POP can go dig itself a hole, as can most web-based mail clients I've used), and I have a few friends who have had the same POP mail account since long before webmail became ubiquitous and who still prefers using their ISP's space-limited mail service for whatever reason (difficult teaching old dogs new tricks, I assume), even if it means only having part of their mail on each device.

Well, it seems the replacing of the HDD will be postponed until tomorrow - I've discovered there are no more free PSU-SATA cables in my brother's computer, so I'll have to buy a Molex-SATA converter tomorrow.
Anyway, I'll let you all know how it went (and mark a post as solution) when it's done.

Sigh... it just doesn't seem to want to work well. I've found I can very well squeeze in the new drive reasonably (I underestimated the space inside the house), I got a Molex->SATA/SATA converter, now it looks like the HDD itself is faulty. The machine hangs for a long while when autodetecting HDDs, then it goes on to load up Windows as usual (since I didn't have to take out the original, it can still boot up), but then it always reboots.
I'll try installing it in my PC to see how it works there and check if it's indeed the HDD's fault or there's something else.