Ok,
Your first problem is that the dsik you are using is outdated. The
disk must contain the same service pack level as waht is installed on
the hadr drive. So, if you had WinXP installed on your hard drive,
then the cd-rom will also have to contain SP3 on it as well. You may
want to research a process known as "slipstreaming". That is a
technique used to integrate (add) SP3 to a XP disk that only has SP1
or SP2.
Not only must you have the same service pack the, version of the dsik
must be the same as the version installed on your hard drive. The
three versions are as follows: XP Home Edition, XP Professional
Edition and XP Corporate (Volume Licence) Edition. In actual fat, the
contents of the disks are virtually identical with the critical
difference being a small file called setupp.ini (yes it is spelled
correctly) that contains a special number called a PID (product id).
My guess is that your are using a Corp disk to try and repair a Home
or Pro disk. You will have to alter the setupp.ini PID before you even
bother with integrating the service pack.
The second probelm regarding not being able to find the cd-rom drive
is due to a sepcial setting in your BIOS. When your conmputer loads,
hit the "delete" key and you will enter the BIOS (setup area). Look
for a section called boot device priority and set your cd-dvd drive to
be the first boot device.
Good luck.