|I assume that you can see something on your screen before Windows starts to boot. If you don't see anything, not even the Dell Boot logo then there is something more than just the boot manager. |
Boot up and before as soon as the BIOS screen shown start tapping F8. You will get a menu prompting for Safe Mede. One of the options should be repair. Select that and follow the prompts.
You may be prompted for a repair disk that you should have created when you got the computer. If that fails and you don;t have a system image then restore to factory defaults will be your only option and you will lose your data..
You cannot download a boot manager. It is something that is created when the OS is installed. It resides on the first sector of the first track on the hard disk and is outside of any file system and is specific to the computer it is running on.