|Try cleaning the laser lens with a laser lens cleaning CD. If you don't have one, you should have one. Most places that sell CDs or DVDs have them, and even some "dollar" stores have them for a buck or two.|
If you have more than one optical drive, try the disk in a different drive - some bioses will only boot a bootable disk from the first optical drive the bios detects.
In that case, if you want to change that, go into the bios and either
- find the list of optical drives - it is often near the Boot Order or similar list - the drive you want to boot from must be first in the list, Save bios settings
- or - a lot less likely - there is no list of optical drives, but more than one optical drive is listed in the Boot Order or similar list - the drive you want to boot from must be first in the list, Save bios settings.
If they're not listed by their model number, they are listed generically, e.g.CDD0, CDD1, etc..
Check your data cable.
NOTE that it has been confirmed in previous Topics on this web site that it only takes a poor connection, or no connection, of one wire on an IDE data cable for a bootable disk in a drive to not be detected as bootable.
It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittent, rather than being reliable.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable.
Try another data cable if in doubt.
Check your SATA data cables. The connector on each end should "latch" into the socket on the drive and on the mboard, or on the drive controller card - it should not move when you merely brush your hand against it near the socket - if it does, mere vibration can cause a poor connection of it - use another SATA data cable that does "latch", or tape the connector in place.
(There is a slight projection or bump on one side of the outside of the connector that "latches" it into the socket - it's easily broken off or damaged)
The same thing applies for the SATA power connection.
If the optical drive is IDE.....
80 wire data cables must have the proper end connector connected to the mboard IDE header - usually that's blue, but in any case it's the one farther from the middle connector on a 3 connector data cable.
- if it is by itself on a data cable, it may be recognized in Windows but not be recognized properly in the bios if the jumper on the drive is set to Slave, or if the drive is set to Cable Select and is on the end connector of a three connector data cable.
- if it is on a data cable with another drive, make sure the jumpers on the back of the drives are set correctly.
Don't mix Master /Slave and Cable Select jumpering for two drives on the same data cable. Mixing Cable Select and Master / Slave jumpering can work in some circumstances but cause strange problems.
Some hard drives - e.g. Western Digital models - have two ways they can be set to Master - Master, single, or similar, for when they are by themselves on the data cable, or Master, with Slave, or similar, for when they are on a data cable with another drive set to Slave - that must be set correctly for the situation.