Note that 7.10 is the most recent version as of now.
Besides a power issue it could also be about your graphics card/display. My laptop, for example, has a widescreen display and a SiS integrated graphics card (no-no for gaming and such), and I recall an older version of Ubuntu (6.10?) showed only black screen while booting - until X started. You probably want to try the powersaving-method first, but if it won't help, you can also try to set (from the boot menu) your VGA to 800x600x16 or something, try "safe graphics mode" and possibly alter the boot commands and replace "splash" with "nosplash" in the kernel line, to disable graphical bootup screen and instead have the texts visible. Helped for me, but it sure does sound odd if your screen won't "come up" at all.