Cannot install Service Pack 2 for W2K

After I install service pack 2 and reboot the system locks up at the startup screen. History: Epox KL-133M MOBO
Windows 2000 sp1
ATA5 80GB Seagate
RAM 512mb PC133
Onboard video and audio.

When I first installed W2K the system would lock up at the startup but when I disabled ACPI the install went through without problem. It is very stable and fast. Problem is this will be a server and I need to install service pack etc. Any help with this would be greatly apprectiated.

Reggie