I assume by the word "hanging" you are actually referring to the machine pausing for a length of time when the Dell logo appears. If this is true, I don't know if your aware that while the logo is being displayed there is diagnostic tests occurring in the background as well a quick virus scan if you have anti-virus software installed. You can speed up the boot time by going into the BIOS setup and enabling the Quick Boot option which will skip over some the post tests. The link below is for the document on your BIOS setup and the Quick Boot option.
<ADMIN NOTE: Broken link has been removed from this post by Dell>
The standard disclaimer.... I don't work for Dell nor am I associated with Dell. I'm not even related to Michael Dell, although there are times I would like to be the first bornson to Bill Gate$.