I've seen this issue on two different PCs with Lubuntu 12.10. After GRUB, there is a blinking cursor and nothing else, I have to force a reboot and after that it works fine. This rarely happens, but it is annoying.
Moreover, I've seen that I have the same problem on my PC with Debian, I've seen it freezing while loading the kernel (just after GRUB), but if I force a reboot, it works fine.
My problem is on an Intel d510mo motherboard, nothing fancy. As far as I can remember, older versions of Lubuntu did not have this issue. I think Lubuntu 11.10 worked fine. I've seen this same problem on an Acer emachines notebook.
How can I find out what the problem is?