can I install any internal cd-rom drive into my performa 5260?

no.
In the 62xxs and 52xxs the original cd drive is at least a 4x apple SCSI drive.
If your drive is dead, best to replace like for like to be compatible with 7.6.1 cd extention.

ok, the harddrive is IDE if you want to mess about with cables and try and get a cheaper, faster ide cdrw drive on the same bus as the harddrive...
driver issues? I have not been there.

it's not dead, it's just that I can't read burnt cd's, data/audio cd's and cds that are meant for PC's. what's up with that?

Ok Bob, assuming that you can read mac
CDs, you are probably missing the "ISO
9660 File Access and Audio CD Access"
from your extentions folder.
First look in "extentions disabled", if there
drag them into extentions folder or use
the Extensions Manager control panel to
turn them on. Restart.
If they are not on your harddrive copy them
from another system or restore your
system from original CD. There may be
other CD format extentions that you are
also missing.

For longer PC CD file name support go
to: http://www.tempel.org/joliet/
and download the freeware
extention"Joliet Volume Access" Version
1.4.2