OK, thanks for that info... I get the feeling that your motherboard chipset drivers aren't fully installed, need updating, or might have been corrupted. Did you repair / reinstall / "FIX" Windows anytime recently?
You can download a fresh copy of the MB chipset drivers for the E1705 from a link on this page:
http://support.us.dell.com/support/...eid=R114079&formatcnt=1&libid=0&fileid=149851
On that page, you'll find two links to download from; one is through a webpage (http site), and the other is a direct link to the Dell FTP server (ftp site). It does NOT matter which site you download from; choose one, and if the download fails or is too slow, try the other site...
The file you want is named "R114079.EXE"; FOLLOW THE INSTALLATION INSTRUCTIONS ON THE PAGE to start the MB chipset driver installation process, then follow the on-screen prompts as directed.
Keep in mind that Windows does a LOT of housekeeping during reboots, so do NOT try to avoid or delay rebooting; allow Windows to reboot and your chipset drivers will be reinstalled. Once you get back to the Desktop, you SHOULD be able to get your external USB HDD working properly...
IF NOT, copy ANY and ALL error messages you see EXACTLY as they appear, and post them here so we can help you analyze this...
The file you need to download is only ~1MB in size, small enough to fit on a floppy disk, so you should have this taken care of fairly quickly, unless you have a more serious problem hiding behind that Hardware Wizard message...
Good luck... Let us know how this turns out... Hope you can update us soon...