Why does some media not show up at all in some drives?

[Rudyard]

I have a RW DVD that I use to test my DVD productions before I burn to permanent discs and all of a sudden when I put it in the drive on my PC (new burner, used to work on old) and my inlwas PC where it used to work aswell nothing happens, the PC says there is no disc in the drive.

It still has the last thing I burnt on it which is a home movie which will play in my DVD player.

Also it works fine on my laptop, I reformated it (quick format, will full format help?) and tried again but still is not recognised.

What is going on and why would discs not show up at all when there is obviously working data on it?

[oldandinthe way]

Perhaps your drive needs to be cleaned.

Perhaps your RW media is deteriorating. A full format might help.

Perhaps the laser is gradually losing strength.

[Rudyard]

My drive is brand new (old one broke with about 2 weeks left on warranty!), do you have to clean new drives before you install them? Or is that something from regular use.....I should have mentioned that all other discs so far work, I will try a different RW and see if its RWs in general or just that one.

I will give the full format a go.

[cyflyer]

Its most probably the RW disc's fault. I have always found them to be similary misbehaving. I think you have to FULL format them between each recording, and QUICK erase either gives you the results you have experienced or screws them up completely.