ubuntu doesn't boot - black screen

At the grub screen (hold down the shift key at boot to force it to appear if it normally does not appear), type e
to edit the boot line. Look at the line starting with "linux" and the parameter root=. If you see root=/dev/sdc, change the sdc to sdb, and boot with control X (instructions on screen). Immediately run sudo update-grub to fix the wrong device. If the root=UUID=..... that is Ok -- then it is some other problem

When does the grub screen come up?

When i start the computer im pressing f9 to get to choose what device i want to start up, is it then or is it after i pressed the device i want to use?

I have tried to press e at the grub screen, but nothing happend. Not with shift either.

What can be wrong :S

The grub screen has "grub" and some version number at the top, and lines starting with "Ubuntu Linux 2.6.... followed by memory test lines,and maybe Windows lines. If you are not seeing this screen, press and hold the shift right after selecting the boot device. When you get the screen, type something like a downarrow to stop the countdown of 10 seconds to boot. Look at the screen, select the first line starting Ubuntu Linux... and type e to edit the line

Do you mean the page you choose between Windows Vista and ubuntu? I have that screen.

I tried to press shift right after i choosed device to start up from, nothing happend.

I have tried a program called EasyBCD 2.0.2.

At this program it has a information option that shows information about my system.

Entry #2
Name: Ubuntu
BCD ID: {3632997b-50a8-11e0-bf02-00269e2e6d42}
Device: Deleted Partition
Bootloader Path: \ubuntu\winboot\wubildr.mbr

As you can see, it says device: deleted partition.

And when i go on ubuntu where i choose between what to start up with it says missing or damaged wubildr.mbr

Maby thats the reason?

Oh, you had wubi on your hard disk and installed to a usb. You probably are not even booting the usb if all you see is the Ubuntu and vista without the memory checks. Go into your bios and look at the boot order -- move the usb device to the top of the list to permanently fix the boot order. Alternatively, a one time change may be possible by typing some character (ESC on my machine) at the vendor splash screen (first one that shows at boot). That screen may have instructions on it for which key to type for selecting boot devices. Select the usb and you should then get a grub boot screen. No need to try editing anything, it seems you haven't even gotten to it yet.

@Ubfan: please attach such question to Wubi project, so bcbc could answer

I have given up this, im installing it on my harddrive instead.

Thanks for the help.