My windows 8 pc wont start up and i cant get it in to safe mode. How do i start up my computer in safe boot?   how can i get a command up when the computer wont start? Please can someone help me.  thanks ever so much for your help.

If you do not have UEFI boot, F8 should help. Or you can use installation media. 5 ways how to safe boot Win 8.1:

http://www.7tutorials.com/5-ways-boot-safe-mode-windows-8-windows-81

i dont have the windows disk, how can i run msconfig.exe when the computer wont start up?  thanks a lot.

Boot into advanced options>find a command prompt>type msconfig.exe in it.  Not sure why you want to run msconfig if it will not boot.  HAve you tried booting from the win 8 dvd?  Have you tried hitting F8 repeatedly on boot?

What caused this?  What have you tried?

Hello,

You can also try to run the system restore to a previous good time for a try.

Thanks,

Please remove any USB devices that are plugged in and verify that the DVD drive is empty.
If there are no devices plugged in and no DVD installed, go into the BIOS of your computer and select to use default settings then reboot your computer.
You can create the installation media for Windows 8.1 here. After creating the boot device, you could then repair your computer from the boot device. You may also want to look at How to refresh, reset, or restore your PC.