WIN98-New CDROM-kills boot

2 year old PC133 with 64 MB RAM and AWARD BIOS. When I replace 6X ACER CDROM with 48X Memorex, cannot boot the 8.4 GB Maxtor HD. Boot stalls immediately at “found CD” messsage. Also prevents using booting with floppy and MSDOS drivers.
Boot fails with CD as Secondary Master or as Primary SLAVE. Both a new 48X and 52X fail same way.

New CDROM will boot, if remove HD, and boot from floppy with MSDOS drivers.
System boots OK with old 6X CDROM and 8.4 GB HD.