Obtain some alcohol and wet a lint-free piece of cloth (special CD cleaning cloths are available that pick up dirt and cleans without solvents) try to polish the CD from the inner part towards the outer diameter. Scratches that are circular will diffuse further the laser as it tries to read the disk so do it slowly so no new ones are created. If you notice scratches from what you’re doing stop and replace the cloth (a fresh cotton ball would also do). Once all the grime and dirt is removed, try reading it on the PC if the cleaning will do. Commercial coatings that have a thin plastic layer applied to the data layer is available but they still sometimes fail.

There are a lot of instances when we find ourselves looking for a driver or software installation cd that is needed to restore some function you have accidentally removed or uninstalled. Sometimes, they just seem to be hidden so good they defy all searching efforts but sometimes they are right in front of you but with tons of scratches due to your daughter playing with it as you accidentally left in on the computer table. These colorful disks are quite attractive to kids and will be dealt with when seen. Unfortunately, scratches that are deep enough to bend the laser can render a disk useless but shallow ones can be polished off. A warning though, this should only be tried as a last resort for this may also crack the disk or ruin it further.

Some motherboards are so sensitive to cooling that no fans connected to the on-board fan connectors would prevent power-up to avoid ruining the processor (this would be the case if you were using externally powered or special/exotic cooling systems) try plugging in a fan or two to see if it works. The worst case is to get the lights and fans working but still there are no beeps, display or other signs of life for it may be a signal of a dead board or power supply.
If your bare systems now functions, you can then add your components one at a time so you can continue to eliminate any problem device. The prices of computer parts have indeed gone down so much that they are affordable to most. If one does not want to spend all the time tinkering and wondering what is wrong then a trip to the computer repair shop would be an easier alternative.