Help, please: Plextor PX-755SA freezing

Hello! Sorry to be asking for help on my first post, but… well, I’m out of ideas.

I’ve got a Plextor PX-755SA (firmware 1.07), and it works, but only sometimes. I’m not sure what the heck is going on, honestly.

Here are the specs:

Athlon 64 X2 Dual Core 3800+
2 GB RAM
Asus A8N-SLI Mobo
Plextor PX-755SA (firmware 1.07)
Verbatim DVD-R (16x)
Windows XP Pro (up to date on updates)
Nero Ultra 7, CopyToDVD, PlexTools Professional LE 3.17

I’ve tried Nero 7 (which works sometimes), CopyToDVD (which has yet to work), and PlexTools (which also has yet to work).

The weird thing is, the programs will freeze, then after a short while, the system will finally freeze, too.

Part of me wants to know why it’s freezing, most of me just wants to fix this and stop plattering DVD-Rs. (I’ve plattered… 12 so far, I think)

Any and all help will be appreciated!