Do you have Nero, Roxio, or RecordNow? If you said yes to any of these, here's what you should get rid of that might help you out (and if not, you should get rid of them anyway):
Nero comes with InCD - get rid of InCD
Roxio comes with Drag to Disc - get rid of Drag to Disc
RecordNow comes with DLA - get rid of DLA
These are packet writing programs which constantly access your drives, and will become a serious headache.
Convert PAL to NTSC or NTSC to PAL------>http://forums.afterdawn.com/thread_view.cfm/167922
ScubaPete's guides------>http://www.dvdplusvideo.com/tutorial007.html
Bbmayo's guides------>http://home.comcast.net/~bbmayo/index.html
My ever-growing movie collection------>http://www.intervocative.com/dvdcollection.aspx/squizzle
Convert PAL to NTSC or NTSC to PAL------>http://forums.afterdawn.com/thread_view.cfm/167922
ScubaPete's guides------>http://www.dvdplusvideo.com/tutorial007.html
Bbmayo's guides------>http://home.comcast.net/~bbmayo/index.html
My ever-growing movie collection------>http://www.intervocative.com/dvdcollection.aspx/squizzle
You may not have Incd installed. Go to the Nero home page, do a search on Incd, you will see Incd cleaning tools. It won't hurt to try cleaning Incd anyway. If it's not installed then we know it's something else
I had the same problem with DVD Decrypter Version 3.5.3.0, I upgraded to the new Version 3.5.4.0, when the window pops up telling me Decrypter does not have "Exclusive Use" I click on Ignore.
Or Try:
Open DVD Decrypter, click on Tools, click on Settings..., click on the ISO Write Mode tab, on the left side look for the Options section and remove the check from the box to the left of line that reads: "Lock Volume - Exclusive Access".
I never had this problem until I installed Plextor's Plex Tools. I have both a Plextor CD and DVD Burner and I have to run the Plex Tools to change the DVD Booktype to ROM and how fast they read discs and how intense/deep they burn.