Thanks to those for taking time out to respond to my post.
I have overcome the problem, firstly the LITEON reader allows the change of Region settings 5 times. When I finally get the DVDs from the US, I can change the Region setting to Reg.1, backup the DVDs bought in the USA with DVD Shrink\DVD Decrypter and when completed change the Reg. setting back to 4. I cannot play the orginal Region 1 DVDs in my player which is Region 4 however, I can play the backups which will be Region Free.
Since I never play my original DVDs and only play backups, that really solves the my problem.