I insert a disc that is pre recorded into side a and insert a blank cdrw into side b and its telling me unreadable disc?

LG CRN 8245B can only read cds , it can not burn blank cd-rw discs. you need a cdrw to burn cds

Your original post said it was blank discs that didn't work.

Now it's ALL discs including pre-recorderd ones. THAT changes things considerably.

Is it audibly rotating the disc once it's loaded?

Do as it asks, insert blank CD-Audio or CD-Music media.

Discs for recording
For recording, make sure to use special audio discs only.
These discs are marked with “Digital Audio” and the logos shown below.
There are two different types of audio discs for the use on this CD recorder:
– CD-Audio Recordable (CDR) discs
These discs can be recorded on once and
play in all standard CD players and CD
recorders, when they are finalized.
– CD-Audio ReWritable (CDRW) discs
These discs can be recorded on, erased and
re-recorded many times and play in CDRW
compatible CD players and CD recorders,
when they are finalized.
– All Philips CD players and CD recorders
with the sticker shown here are CDRW
compatible.
To ensure proper working of the set we recommend the use of Philips audio CDR and audio CDRW discs only.
Note: Do not use a computer CDR or CDRW as recording will not work!

Go here and download the manual. You'll need it.

http://www.p4c.philips.com/files/c/cdr602_00s/cdr602_00s_dfu_eng.pdf

You are probably inserting blank computer discs, eg 650 or 700mb rather than blank music CD-R or CD RW`s which this machine is designed to work with. The correct discs are labelled "music audio" or 80 minutes. You can only use these types of discs. Why? When these recorders first came out, it was a way of battling piracey in copying discs. I believe there is a "hack" to enable this player to use blank computer discs.
SMA

I found out that memorex cds that have on the package (for use in audio recorders)work every time.They're red label packaging,I hated buying cds only to find out they dont work. Dont forget READ THE LABEL look for (use in audio recorders)

First make sure your cdrw disc is blank. If it is blank try another good known cdrw brand disc and burn it in 12x speed for a good burn.

If it still fail check the software side of your cd rewriter first and lastly the cd rewriter unit.

Have you tried a disc cleaner yet?

You can try other brands of audio cdr but it sounds like your laser is on it's way out. Some find cdrw's still work after cdr's have stopped being recognised.

To fix this problem, buy CD-R Blanks with word MUSIC CD-R MUSIC

The laser lens in your drive might be dirty or failing. Try the following solutions: Clean the laser lens with a DVD player lense cleaning disc. Lense cleaning discs are available at many electronics retail store. Sorry i can't help you more.