Can you post a log from ImgBurn
You can find them by pressing HELP and choose Logs and the graph data is just above and will open where they save to.
You should then arrange by modified and use the last one listed
If it was my drive I would update anyway with the extracted EXE to 2 files.
If your happy with your drive as is then leave it alone.
EDIT if your running dual boot then boot into vista once firmware is updated in vista the drive will still use that firmware in XP afterwards.
seems a bit much if they have limited the installer to vista (did you try it) as really 32 bit should be the same unless they look at product id in installer.
I also extracted the files so that the installer is not needed if it does indeed block XP
653L_0714.rar
when you say same media / media in one box or the next one you order is never the same.
What size psu is in your new comp or can you not put the drive back into the computer you took it out of.
My liteon 20A1P is very poor for writing Wii games using good quality media + or - at 4x 1 works 2 do not. It's more to do with your writer than the disc's.
As soon as I started writing the same disc's using one of my benq 1650 @4x everyone since has worked.
So if the your LH-18A1P is anything like the 20A1P you might be better off getting another drive to do Wii stuff.
Or get some DVD+R and set the booktype to DVD-ROM using your liteon and see if that makes a difference when burnt at 4x
My pio 111 , 112 does not have any issues with verbatim media.
MCC 03RG20 (not sure i have tried any of these on my 112 or if I even have some, I think the 16x + and - I got were Tayio Yuden)
There is something very wrong if your drive only allows to burn onto dvd-ram.
which version firmware is in the drive.
what brand media are you using as well.