You wouldnt be the first person to end up with bad recovery disks. In any case, since you have a startup problem, you first need to run startup repair from the System recovery options. Startup Repair
If you are not able to reach the system recovery options, you can try doing it from a Windows 7 disk. Since you have an OEM computer, I presume you dont have a regular install disk, you can still run them from a system repair disk. See option 2 in this tut. System Repair Disc - Create
FYI, you can also launch factory restore from the hidden partition instead of using the recovery disks. For this, do the following:
As the computer starts, press F8 until the Advanced Boot Options menu appears on the screen. Press the <Down Arrow> on the keyboard to select Repair Your Computer on the Advanced Boot Options menu, and then press <Enter>. Specify the language settings that you want, and then click Next. Log in as a user who has administrative credentials, and then click OK. Click Dell Factory Image Restore.Follow on screen prompts.
If all this doesnt work, come back and we'll tell you how you can clean install windows and activate using the COA sticker key.