Ok, weird problem, my dvd drive seems to be a bit tempermental, sometimes it won't let me watch dvds on my computer.
Win media player (or any other media player) comes up with error "this dvd can't be played at this time", or something like that, despite the fact that if i explore the dvd all the files are viewable.
The only way i can get them to work, is to eject it and put it in until by chance it seems to work and the disks aren't scratched cos they're new (xmas presies ).
sounds like a software problem rather than hardware
any ideas?

my spec.
win xp home
xp1600
soltek kt266a motherboard
geforce 4 4400 gfx card
384mb 266mhz ddr ram
soundblaster 5.1
ibm gxp 60, 20gig
100Mbit lan card
Winfast tv tuner

What's the model of your DVD drive?

Install PowerDVD and try playing them with that.

as far as I know windows media player still has to have a DVD software playing program in order to view DVD's like WIN DVD or Power DVD. there is a freware program called zoom player.

It could be one of a few things:
First we need to know where abouts in the IDE chain it is, do you know what it is set to master or slave, and which channel it is on?

If you are feeling brave check if there are any firmware updates for your DVD drive here: (You might even be able to get patched RPC1 region free firmware, but you didn't hear that from me )
http://forum.firmware-flash.com/portal.php