First of all, apologies for the time that it has taken for an answer. Somehow this question seems to have fallen through the cracks.
Most recent Dell computers ship with something called a "Recovery Partition" which takes the place of an actual CD or DVD used to reinstall Windows. (Microsoft pushed Dell and other companies to do this instead of shipping CDs or DVDs as a misguided attempt to fight piracy.)
If you turn your computer off, and then turn it on and press & hold F8 or F12 during bootup, and look for "System Recovery" options in the BIOS menu.
If you do not have this partition and do not have any system disks that came with it, you will have to contact Dell support to see what your options are. Fortunately they have a very active community at
where you should be able to find people familiar with this particular problem. There are a number of Dell support options listed
on this webpage
including phone support and online chat.
I hope this helps, and again, my apologies for the delay in responding. It may help in the future if you post computer related questions to managemylife.com/mmh/questions/category/computer-project
but I will be monitoring this post for further replies in case you need more assistance.