Windows 7: Cant boot from laptop HDD modular bay

Hi, I have a dell e6410 laptop with windows XP SP3 on my internal HDD. I have another HDD with windows 7 located in place of my optical drive. I want to be able to boot to either the internal XP or the modular bay Win 7. During boot sequence, which is set for internal-> modular bay-> CD/, I select F12 and choose 1 time boot to modular bay but it skips over my request and boots to the internal drive Is there a configuration I need to set? Both harddrives are labelled as C:\. My laptop is hot swappable but it errors out with message" Cannot enable because it conflicts with another resource" So I can neither boot to the modular bay nor can I insert it successfully with XP already running. Anyone have Any Ideas?. By the way.., I installed windows 7 on the Modular Bay HDD while it was installed in the internal bay then moved it to the modular bay if that makes a difference. Any help would be greatly appreciated.

Can you boot to the modular if the XP drive is disconnected?

Have you ever been able to boot the modular?

Have you experimented with different motherboard ports?

Yes, I can boot to the modular drive if I remove the internal drive. When I first installed the internal/ modular combination, All worked fine. Then just out of the blue it started to malfunction and I honestly cant remember if I caused it or not. Im not sure I understand what you mean by trying other ports unless your asking have I tried booting as a cd\dvd instead of modular, which I did try.