IDE Errors in Device Manager....

After reading what Kodo has pointed you to, try the following:

1) disconnect the CD drive from the cable and only boot with you hard disk connected
to primary. Do you still get the Exclamation Point on the primary?

2) try booting from Win98 Startup boot floppy? If that works and you can see your CD ROM
drive, you may have to put the Device= drivers back into config.sys and you have
to also add the mscdex.exe back into autoexec.bat. By looking at the Win98
Startup floppy you can see how what those lines need to be. Look at the config.sys
and autoexec.bat files on the startup diskette. Copy the relevant lines out
of these into the config.sys and autoexec.bat files on your c: drive. You normally
do not need these lines added to autoexec.bat or config.sys but sometimes
after you boot windows once with these, you can remove them and it will find the
CD ROM thereafter.

Other things to try:
1) check to make sure both ends of the IDE cable are properly inserted.
2) make sure power connector is properly inserted.
3) checking IDE cables. Do you have a new one you can try?
4) See if CD ROM will work as a slave off the master.
5) May need try removing your primary & secondary IDE controller via
MyComputer -> Device Manager -> Hard disk controller
Then upon reboot windows should put the drivers back in.
It may be best to boot in safe mode while doing step 5. Also,
when windows starts up and detects the new hardware it will
probably ask to restart. Say no if it has only found the primary
ide controller it should also find the secondary. Now after you
finish booting all the way to your desktop you should manually reboot.