After i install SP2 on XP home, Windows never loads successfully..

I recently had to buy a new hard drive. I have installed Windows XP Home
Edition (it is from an upgrade disc). I have installed the motherboard
drivers. I have used Microsoft update to get the critical updates. Then my
system tells me that I need to download SP2 in order to get any more updates.
After I download and install SP2 the computer need to reboot. From then on,
Windows never loads successfully (with the exception of the three safe
modes).

Now I can go to any restore point.
I have tried reinstalling all updates.
According to Microsoft update, I have to install the critical updates before
I can download SP2.

What other options do i have?

thanks
-Shawn