Computer issues

Here we go again. I've not had good luck with computers this year.
I go to start my computer today and no, it won't do that. It goes from the apple screen
to the blue screen to the home screen and just before it finishes it returns to the blue screen
then the home screen, then the blue screen then the home screen in this endless rebooting loop.
So, I tried starting from the install cd, ran disk repair, the disk is fine.
Then I tried starting from safe mode... and it starts, so then I used carbon copy cloner to make an identical copy of the hard drive. But my external hard drive didn't have enough space, so I deleted and then made the copy.
So, now I'm making a second copy on a different hard drive (I ain't takin no chances...)
and then I don't know what to do.
Reinstall the operating system?
System restore?
Even though I have backups it's a pain in the ass to rebuild everything.
Why can't it just work without problems?
What is the deal?
Well, at least the current backup will take three hours so I've got time to kill.
I think it's time to order pizza and watch a movie.
Silly computer.
(oh, and I'm sure you were wondering how I wrote this, I'm using husbands happy machine right now... his works fine...)