|"I've got the "Reinstallation CD Microsoft Windows XP Home Edition""|
Is it the original one that came with the 8300? If it isn't, it should be bootable, but you probably can't use it for a Repair installation.
"I've changed the boot sequence to diskette, CD, HD and still not booting up."
That's correct, but did you SAVE bios settings after you did that ?
( If you have a floppy drive, make sure there's no disk inserted in it.
This probably doesn't apply, but remove any USB flash drives or USB external drives before you attempt to boot from the CD. )
If yes, do you have more than one CD or DVD drive on the 8300 ?
If yes, try it in the other drive.
Some bioses will only boot a CD or DVD from one of the CD or DVD drives.
If that doesn't apply or if that doesn't help...
Try using a laser lens cleaning CD in the drive. 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 that doesn't help..
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.
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.
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 that doesn't help, if the disk boots fine on a different computer, if you have only one CD or DVD drive it's probably defective.
You should see a line while booting early in the boot sequence " Press any key to boot from CD" or similar - you must press the stated key while that line is on the screen.
Setup will auto reboot the computer two or three times. DO NOT press the key to boot from the CD after Setup has started.