ok got a idea, I know how to fix this I think... look in BIOS on dells at top, find ur Boot options, 1 make sure you have enabled USB- DVD- SATA- yur hard drive.. Then put boot option #1 boot from CD/USB #2 Boot from NETWORK, #3 boot SATA/ ATA/ULTRADMA... PLus at bottom look for Errors, usually changing memory will throw a error, or any other device errors.
I don't know yet how to help by remote in preboot... theory to create Administrator password, then maybe connect that way, can change when fiished. when replacing or fixing aka something on your laptop your elgible for a OEM DVD from who gave you the laptop/fixed a hard drive for example..
I am having a lot of difficulty typing on lomcn, don't do it on my facebook or anywere else.
ps if not running anything higher ie win8 under Hard drive run as Legacy- win7 is still legacy support
Hit F12 for options
I will try to get over to my rl bros and Upload a win7 ISO, and XP sp3/ black edition too