Macbook boot problem...HELP!

I've got a big problem, and urgently need help....

I've had my Macbook since last November. I had a lot of junk installed on it, so I decided to format and do a clean install today.

I installed the OS with no problems, and did a custom install without all the language packs, etc...

It boots into OSX, I decide to start installing Firefox and that kinda stuff, while at the same time I run software update to get all the new uppdates for OSX. Maybe it was because I was instlling multiple items while software update was running, but I got an error message saying that all the programs on update could not be installed, so I rebooted.

After rebooting, it gets stuck on the screen that comes up with the status bar when OSX is loading. Left it there for 10 minutes, and nothing. Tried 4 times, until I decided to do another format in case there was some corruption.

I reformated once again, I go to software update again, and choose for all the updates to be installed, except this time, I leave the computer alone while it's downloading and installing. Everything supposedly installs, and it asks me to reboot. After 10 minutes of waiting on the white screen with the apple and the little grey crank wheel spinning, I assume it's stuck, so I hold down the power button to reboot. Same thing. It is STILL stuck on the spinnning wheel and it's been 20 minutes. WHat the heck is going on?

THe only thing I can suspect is that there's something wrong with the Apple updates that I'm downloading, because as soon as OSX reformatted, I rebooted twice first, to make sure that before I installed any updates that it would reboot, and it did. Then I go and download and install the updates, and it's stuck in the white apple screen and it wont boot up OSX.

How long should the reboot take after I install the updates? Not 20 minutes I'm assuming, correct?

What is going on here, and what should I do!?