Unable to dual boot

I have recently installed ubuntu 12.10 on my computer (with the specs on my bio) using the option "run alongside windows". before I installed it, there were about 150 GB left on my hard drive, and since that part became partitions after I installed it, I was sure that it was installed. Then when I restarted, nothing happened. I tried reinstalling Ubuntu, nothing happened. I can't seem to find a dual-boot menu on my bios either. Can anyone help me with this? or should I just stick to Wubi (which is woefully slower and can't be used as a second resort)?

What happens exactly when you try to power on the computer? Are there errors or does the screen just stay black?

So the system doesn't boot into either OS?

Did you allow Ubuntu to install the Grub boot menu at the end of the install process?

That sounds like it maybe the issue as it maybe corrupt for some reason.

It just boots to windows 7 as if nothing changed. No error shown at all, and I can still boot with my USB

try easybcd it will recognise ubuntu to the boot loader if it installed correctly

Did you install grub?