I see you're using Win98 which makes this a lot easier than if you
were using a newer OS (2k or XP). Whoever told you to delete
everything from device manager was right - well, almost right. The
thing is, you need to do that in your current computer before you
remove the hard drive. To make things easier, here's a step-by-step
list of what to do:
-Make sure you have drivers for everything that will be installed in
your new system (sound, video, network card, etc...) You should either
have these on a CD or on your hard drive unzipped in a folder
-Boot up your current system with the hard drive still in it. Go into
device manager and delete everything.
-Shut down the computer, remove the hard drive, and put it in the new
-Make sure the jumpers on the hard drive are set up correctly for your
new system. If it's on the same ide channel as before in the same spot
on the cable you shouldn't need to worry about it.
-Go into the bios and set up your hard drive, in most new bios's you
should be able to set it to auto and it should detect it just fine.
-Exit the bios and boot up Windows. It will likely take a long time to
load but you should have no problems. You'll probably be prompted for
drivers which you can install now.
I've done this very thing before (actually, I did it without deleting
everything in device manager - it was a bit messy afterwards but it
worked) and you should have no problems with it. If somehow this
fails, you always have the option of reinstalling Windows over itself
which should work as well. As well, if the drive just won't work in
the new comp you should be able to put it back in the first one
without much hassle.
Hope this solves your problem! If you need any clarification, please
feel free to ask before rating this answer.