has anyone experienced this?
Pc working just fine after a new format and reload. After a few startups the Cd Rom stops starting up.The system will not see it.

If I hit the restart button on boot up , it then loads the CD Rom and everything is fine.Never saw this one.

I don't know for sure...but I think it started after loading MS Office 2000.
Note: this was one of the problems I was having (not to mention lots others) before I reformatted and reinstalled the PC. This is an older Acer machine that I can't let go. It's a good little runner.

Any clues?

As it's an older machine, I'd check the cmos battery, just to be sure it's voltage is within acceptable levels. Also run a virus check (preferably online), as this sort of activity is one of hte favourite tricks of some viruses.

How would I check the cmos battery ?

Also:
-Make sure all of the CD-ROM drive's connections are secure.
-Connect it to a different power lead.
-Install a new IDE cable.
-The drive may be bad.

A drive that is not seen on a cold boot but is seen after a restart would indicate that the drive is not ready (has not completed its internal checks) when being accessed by bios. Since it isn't ready, bios doesn't include it in the list of devices.

This could happen for any number of reasons:

1) Bad Cd-rom
2) Bad controller (motherboard)
3) Bad power connector or data cable
4) Bad PSU
5) Too fast a boot process.

You may be able to slow down the boot process so that the Cd-rom can catch up:

1) Older computers may have a boot delay setting in bios.
2) Most bioses have a "Quick boot" feature that allows you to skip some of the POST. Disabling quick boot will increase the POST time and may solve the problem.
3) Enabling "Floppy Drive Seek" in bios will delay the boot process.

Finally, if nothing works, you could just live with it. A new Cd-rom would probably also solve the problem - you could replace it with a Cd burner which I've seen on sale lately for $20 after rebates.