Is it CD, MotherBrd, or Riva TNT?

[Dagwood]

I have been having an annoying problem I hope someone might be familiar with. first, I have the following setup...Fresh home from the store.
Asus P2B (Bios 1007)
: Intel PII 450Mhz
: 128Mb PC100 SDram
: CL TNT Riva (latest Bios & Drivers)
: CL Sound Blaster Live
: CL 40x Cdrom unit Mod # CD4020E
: Supra 56k PCI modem
: Adaptec SCSI ISA
: Windows 98

In NHL99 if I can manouever thru the setup screens fast enough, I can play a game no problem, in fact I'm very impressed with the graphics. If I'm not fast enough, the game freezes while in the setup screens. Once it freezes, I need to eject the CD and that releases it, I get a read error and I'm back to my desktop. In the game, I have no problems Pausing, changing lines, coaching strategies.....etc

In Descent Freespace I can fly the missions again without any problems, but in the briefing screens and option screens, My Mouse will not activate any buttons even though they are still "Highlighting" as if selected. To get the program to recognise my mouse clicks, I again have to eject the CD in & out during each freeze. I've searched for similar problems but have not found anything yet.

I rigged up a fan to blow across the Riva TNT Chip to cool it down, I thought it might be a overheating prob. but it's not

Any Ideas would be greatly appreciated.

Thanks