No boot screen

Hi, I received my alienware on November 10 2009. I loaded up the computer everything work fine. I decided to install a fresh copy of Windows 7 64bit and the drivers from the resource cd. Everything works fine. I installed a few programs such as word and some games. I restarted the computer and I no loger see the boot up screen with the alien head nor the windows 7 logo any more. It boots into windows login screen eventually. I don't know whats wrong with the computer, tried gooleing, but found nothing yet. Any help would be much appreciated.

*Update. 10 mins later.
- I thought it was the nvidia graphics driver, so i uninstalled it, and restart. Now i see nothing at all. Nothing. Not even windows login screen. I'm updating this on my desktop.
- I "have" an alienware M15x, gtx 260, i7 processor, 4gb ram.

*Update. 15 mins later.
- I decided to unplug the laptop (i read somewhere that the alienware had problems with the hybrid graphics options in bios), and the boot screen and windows went on fine. I'll check this out, I'll update on this case anyone has the same problem.

 

*Update. 15 mins later.
- I decided to unplug the laptop (i read somewhere that the alienware had problems with the hybrid graphics options in bios), and the boot screen and windows went on fine. Guess i fixed it. But why? ummm. I'll check this out.