The "closing" of a burn CD refers to stopping any more data being written to the CD. ie if you burn 300Mb of 650Mb you could leave it open to add more later.
Anyone can read a CD as long as their CDROM can read it, got nothing to do with if it is closed or not.

If you are backing up data and want to add more don't close the CD.
If the CD is full it will close itself.

Some older CDROMs can't read CD's with more than one session(recording) or rewriteables, some very old ones can't read written CD's.

As to the program to use CDRWin is good, Adaptec is crap.

I use NERO 4.07 and have little to no problems with my crappy old OEM 6x2x2x burner. Copy protection, scratches or dirt on CD's will cause problems, ie make you a coaster. I burn to a rewrite and then to record once if all OK.

Mine is IDE but always scans for SCSI at start.