I CAN RUN VCD BY LG COMBO DRIVE BUT I CAN'T RUN DVD ?

http://download.cnet.com/dvd-genie/3000-2139_4-11629.html

Modify region code for software-based DVD players
or free to try or buy

http://download.cnet.com/riodvd-region-free-player/3000-7970_4-10463982.html

Play and watch your favorite movies in DVD, VCD, and SVCD formats.

hope it helps

This is due to a weak lens
Sometimes this type of problem occours due to excessive use of the drive in burning cd/dvd

Trying some leans cleaner may solve your problem

Combo

Combo drives have 2 lasers inside of them. An IR laser to read CD/VCD and a red laser to read DVD. It sounds like your laser to read DVD discs is dirty or has developed a fault. A replacement drive would be your best option as they are now very cheap and it will resolve the issue quickly.
Hope this helps,
www.PuterCare.com

try these steps

) Close all open programs
2) Click on Start, Run, and type REGEDIT and press Enter
3) Click on the plus signs (+) next to the following folders
* HKEY_LOCAL_MACHINE
* SYSTEM
* CurrentControlSet
* Control
* Class
* {4D36E965-E325-11CE-
BFC1-08002BE10318}
4) This folder is the DVD/CD-ROM Drive Class Description in the registry. Look for any of the following names in the right hand column.
* UpperFilters
* LowerFilters
* UpperFilters.bak
* LowerFilters.bak
5) If any of the above keys shown in step 4 are listed, right-click on them and choose Delete
6) After deleting the keys, close the Registry Editor
7) Reboot your computer

If not reading DVD is a pattern (it won;t read ANY DVD, no matter if it's a burned one or an original movie) then the lens is dead. I'm afraid you'll have to go get a new one (new drives are very cheap, usually around 25-30$)

DVD NOT DETECT ONLY DETECT THE VCD
PLEASE GIVE THE SOLUTION

why my dvd cann't read dvd movie

VCD play but DVD not play
and show a message (no disk) when insert DVD in combo drive

I suspect you do not have a DVD Player there are some about youcan try this one. Go here and download some of the Trial ones they offer and see if it will play your DVD..... http://apps.corel.com/lp/ivi/index.html