Disable driver signature

[nnabuchidelight]

I really need help with my Dell PC
I tried to boot the PC but it is crashing into a blue screen, I have tried to disable the driver signature through the startup settings but the menu does come up

I also tried using command prompt,all to no avail

 

[william p]

It would help if you told us what Dell PC you have. But my first suggestion is see if it will boot from another device. I like Linux live DVDs, but an OS on a bootableUSB stick will work also. This willl bypass any HDD or OS issues.
Almost all Dell computers have diagnostic LEDs on the front. Are there any green or yellow light there? Flashing or steady?
A look in the owners manual for your computer may tell you something if you have any of those.