IDE CD sounds but not view data

If you start the Device Manager does the problem CD drive have an exclamation mark in yellow (!) next to it?

No. It hasn't.  And in the properties the system says that the device behave well..

Try taking a look at http://www.acer.com/aac/aod/support/ftp.htm#CDROM and get the most recent driver for your drive.

if you have a TX board, make sure it has the most recent BIOS version.  some boards had trouble with initial versions that didn't handle the acer controller reliably.  a flash bios upgrade solved the problems on many boards.

is the cd-rom drive connected via a 40pin data cable to the motherboard (same as the drives) or the soundcard?
Is it on the same cable as the drives? Check cable orientation (is the colored cable beside the power input to the cd drive?). change the cable.

this is almost 100% definite hardware level communications problem.

to sorceror :
I have examined drivers but are all for dos and not for win95.

Did your CD work before you installed your Zip Drive?
If you have a SCSI device and you install a ZIP Windows 95 has many problems with different drivers. If it is possible reinstall Win95 without a ZIP-drive and after this test if your CD-Drive work correctly.

I have removed the driver "IOMEGA Parallel Port Interface" and the problem still remains. Anyway I'm searching a solution that behave well with all drives in current configuration.
Thanks!

Please reply...is the cd-rom drive connected via a 40pin data cable to the motherboard (same as the drives) or the soundcard?
Is it on the same cable as the drives? Check cable orientation (is the colored cable beside the power input to the cd drive?). change the cable. You will have to open the case to tell this.

the cdrom is connected via a 40pin data cable to the motherboard (another cable and connection is for the two hd).
I have not marked correctly the situation :
the whole system behave perfectly if in the acer cd drive is there a sound cd !!! the problem is generated if I put in the same cd drive a data cd !!
sometimes it hangs the explorer, some times it return a system error which (translating from italian) is :
error OE in xxxx:xxxx in VxD CDFS(03) + xxxx. It was called by xxxx:xxxx in VxD voltrack(04) + xxxx.

So it seems that it don't want to read CD file system !!!
I know it's really strange, but this is the scenario...

There is a vague possibility that your heads could be damaged, how old is the drive? Probably more likley to be a corrupt driver or registry (or a bad data cable) have you tried changing the 40 pin cable on the CD?

Ikon says, "Probably more likley to be a corrupt driver or registry".
If you go the route:
-----
After a major clean up, you notice that the size of registry remains the same. It's just like how DOS
deletes files on the hard disk. The files are not really deleted, they are just floating.
In the registry a removed key becomes an invisible existence to the reg editors. You can export keys
that are recognizable by the editors to a temp file, then use the same temp file to reconstruct a new
registry. And this is how we remove those invisible footprints.

WRPV3.ZIP is the Best Backup/Retsore I've Seen. http://www.webdev.net/orca/ Search WRP
Step1: If you have other .dat files in Windows Directory, move them to a Temp directory.
Step2: Be sure to have a reg backup already.
Step3: Open reg editor and export "all entries" to a reg file (MyReg.reg).
Step4 Exit to DOS. Go to Windows directory.
Step5 :Deltree reg files, e.g. deltree *.dat /y
Step6: Use the same syntax, regedit /c MyReg.reg. Done!

After the process, please exam your system thoroughly. You can never tell from a seemingly healthy
system a near-death registry. Also keep the backup for a while before update it.