I already searched the forum for this problem and found a bunch of fixes but none of them worked.
 
I have a LG GSA-H20L SATA DVD drive that opens at random but 70% of the time its while DL'ing or web surfing (but not always).
I just built this system as follows;
Asus M3N-HT Deluxe Mainboard
Athlon64 X2 6400+ Processor
4GB Crucial Ballistix Tracer DDR2 Ram
WesternDigital 74GB Raptor Drive
and said DVD drive.
On Windows Vista64 Ultimate
 
I have updated all my firmware/bios for all devices that I could find an update for (there isn't one for the LG drive).  I have installed all updates for Windows and yes it is a legit copy, full version not an upgrade and it was a clean install.
 
I have Panda Internet Security antivirus running, it hasn't found anything.  There was a thread that mentioned a possible specific virus, I did a search for it and came up empty.
 
I purchased the drive from NCIX.com and had it RMA'd this is the second drive and it is doing the same thing the first one did.
 
If anyone has any new or different advice I would like to hear it.

download another antivirus, and try that