dbarton:
Controllers for SATA drives essentially can be configured in three ways: First is RAID. I won't go into what RAID is here, but if you only have one hard drive RAID isn't even an option for you, so don't worry about it
. The other two ways are as "IDE" or "AHCI". IDE is the traditional way that hard drive controllers have been configured, it is essentially how all modern parallel ATA drives are connected. You just found the main advantage of selecting to install as IDE: since IDE has been around for a long time, almost everything works with IDE drives without much effort. The other way to configure SATA controllers is as AHCI. Essentially, AHCI provides a couple of advantages over IDE: it enables something called Native Command Queuing (NCQ) which makes the drive perform better, and it allows you to "hot swap" SATA drives. The drawback is that Windows XP installation will not natively support AHCI controllers, so you need to provide the drivers before installation begins by using the infamous F6 key.
You can check
here for more details on AHCI, and
here for more info on NCQ.
There is one easy way to find out how your laptop is configured: if you go into the BIOS, there probably is a way to select the configuration of your SATA controller as either IDE, RAID or AHCI. If you find it, it will show what the current configuration is. If it says IDE you can just go ahead and install XP. If it says AHCI, you may need the AHCI drivers for your laptop's SATA controller. You can find them
here. I do not know Vista, so I do not know if there is a simple way to find out your controller' configuration from within Vista, without having to enter the BIOS.
For HP machines I believe you can access the BIOS by pressing F10 as soon as the machine is turned on, before windows starts to load. If F10 does not work, try F2 or F6 (Other brands also use the Delete Key or F1, but I believe HP uses one of the three keys I mentioned). What specific model of laptop do you have?
Finally, there are many MANY people in this forum who are infinitely more knowledgeable than I am. So, if anyone wants to correct anything I said, please feel free!
EDIT:
When you go into the BIOS, do NOT change the configuration of your controller (i.e. if it says IDE do not change it to AHCI, or viceversa). I believe that it can cause a blue screen error in Windows.