Hi jakalad and Welcome to the Forum!
Well, I would say that it may be Indexing the drive but this doesn't seem likely since it hangs at that starting screen.
Have you tried disabling the drive in the BIOS and see if your machine starts normally again? If so it definitely is this drive that's causing the slow start, but I can't really think of why that may be right now. I would start be checking the BIOS settings for your IDE setup and make sure that this drive hasn't been added as a boot device also. I know some stupid BIOS's will automatically put a newly installed drive as the 1st boot device sometimes (I know, it happened to me with a Phoenix BIOS)
Also, once you do finally boot, do you have any Event Viewer entries about this or any devices shown in Device Mgr with the yellow exclamation mark? And check what Disk Mgmt applet has to say about this drive once it boots with it installed/enabled again, anything may help us.