I think we need a bit more clarity before anybody can help you.
what i think you're saying is that your keeping you're IDE drive as a backup, just with data on it, no OS. And you're SATA drive as the dive with the OS.
Are you installing XP onto the SATA at home, then taking the drive out the computer, sticking it into a computer at work and then trying to put drivers on it? Then taking it home and putting it back into you're home machine, booting it up and fining the Master Boot Record (MBR) is not working, which gives you NTLDR errors?
If you're doing this there are so many problems you could be running into.
I'd suggest that you install XP onto you're SATA drive, on the machine that you want to keep it in and leave it there, do not take that drive out of that machine. Also when you install XP onto it, only have the SATA drive plugged in, no ATA drive. Once you have XP on that drive then plug you're ATA drive in, but the first time you boot up after putting the ATA drive in, make sure to set the boot order for you're dives in the BIOS, set the SATA drive as the primary boot drive, this way if you have XP installed on both drives it'll look in the SATA drive for the MBR, so even if you have an old MBR on the old ATA drive it wont try boot into the XP installed on the ATA drive, this is also why you only have one drive plugged in when you install XP onto a drive, it's just an extra way of making sure you know what's installed on what drive, it's a bit excessive i know, but it's always better to be on the safe side.
OK, then leave those dives in that machine, don't take them out. Get a flash disk and take that to work and copy the drivers onto that, take that home, copy the drivers to you're computer and install them there.
If you were to take you're SATA drive out of your home machine, and plug it into you're office machine, it'd probably boot off what ever drive it has in it already or off a network, i have no idea how that's set up, but then when XP boots up may be checking for MBR's on other drives, and re-wright them to be secondary drives, so you may see your SATA drive with everything on it, but when you plug it back into you're home machine you no longer have a MBR on that drive, you still have the OS and all you're files, but with no MBR you're computer wont boot into that windows, which is I'm guessing why you keep getting these NTLDR errors.
Another problem is when you install XP onto a drive it configures a bunch of settings to that computer, so if i have an AMD, it'll set a bunch of AMD specific things in that install of windows, then if i take that drive and plug it into an Intel machine it wont boot, because that windows installed to be used on an AMD machine, real life is a bit more complex but i'm simplifying for the sake of clarity. What may be happening to you is that you install on you're home machine, then stick the drive into another machine, and Windows gets far enough into booting to realize that the system is configured differently and then change its self to work on your work machine. Then you stick it back into you're original machine and it tries to boot you're work machine configuration but doesn't get far enough to realize that the systems configured differently and just hangs somewhere in the process of loading windows.