Odd windows 2000 problems...

OK, my grandparents wanted me to upgrade their computer because they were having endless problems with Windows ME.  So I took windows 2000 and began to install it.  I don't remember exactly what screen it made it to, but it never got very far(never entered any information.)  I appeared that it was thinking off the CD and HD, but nothing else...

Just yesterday, I installed 2K on my custom Cyrix, and it works great, never gave me any problems...  So whats the deal?

HP Pavilan(Grandparents computer)
Celeron 750MHz
64M RAM
50x CD
20G HD
Onboard intel video(sharing 16M of SDRAM)

My spare Cyrix
Cyrix 6x86 233MHz
128M RAM
52x CD
3.2G HD
Onboard SiS video(Sharing 8M of SDRAM

I knew their computer was cheap, but cheap enough that a Cyrix 233 was faster!? ???