I happened to come across a friend of mine who had a problem
installing Win98SE. Even though his system used to work just fine
since he got it, the day he formatted the drive to reinstall
everything again, he started having problems booting from the Win98SE
CD-ROM to proceed with the installation.
Anytime he booted with CD-ROM support, he would get a message saying
"scanning pci bus using mechanism #2" and get stuck right there.
Basically, I asked him to remove one of the CD-ROM Drives he had
installed and try with only one drive in the system, since this
message would appear after the Win98SE booting had loaded the ASPI
drivers. Unfortunately, that did not work.
Finally, by trying to think as simple as possible about this issue and
taking the message as literally as possible (PCI, PCI, ...,

, I
suggested him to take out all the PCI cards he had installed in his
system and just leave whatever was necessary to boot up the system
(which was the Video Card). Next time he tried, the boot process went
through and he was able to install Win98SE. Obviously, I told him to
install the cards again after installing Windows.