ok, I need to get this straight.... from your last post, riptorn, it kind of sounds like you tried to start up the laptop with both devices attached again. So, could you answer these questions for me?
startup the laptop with just the printer attached, is the startup slow?
startup the laptop with just the external hard drive attached, is the startup slow?
in any case, updating drivers for both would be a good idea.
My own computer always does a USB check when starting up, to check whether it can start up from a USB device. My own guess would be that your laptop might be trying to do the same. To check whether it is doing this, you will need to go into the BIOS, usually done by hitting delete during startup (it should say so on the screen...I don't know if Dell also uses the delete button). In your BIOS, there should be a Boot section. In this boot section, you should see something which refers to the start up order. Go into it to check which devices it checks first to start up from.
Personally, I like to have it at DVD/RW drive, then my internal hard disk drive. I only enable the USB option if I need it. (and it can come in handy if you really mess up your system and you've backed everything up to an external hard drive....)
I don't know if that's the issue, but it might very well be. Just do a quick check to see.
Also.... does your external harddrive have its own power supply, or does it use your laptop's power?