e-machine and gateway don't make drives. So I assume you mean the drives that came inside
you could put your original main drive into the second computer, but if you try to boot from it, you'll encounter way to many problems to try to fix. For example, the original Hard drive probably had windows configured with drivers for the system board, Video card, hardware controllers, and all sorts of other stuff inside the original computer. So the best you could do is use it for data. And you cannot use most applications that are installed on the original drive, even if you find the exe and execute it, since all the registry settings for the app are on the other hard drive which you can't boot from properly for reasons previously described. The best course of action in this case would be to simply grab the data you want off the original drive and reformat to use as a Data drive.
