The answer to this question lies in understanding judgement day from the Jehovah's Witnesses point of view.
We do not believe persons are resurrected and judged worthy of eternal life or eternal anihilation based on their imperfect previous existence. Rather those sins are blotted out or paid for by death.
After resurection all persons righteous and unrighteousness in their previous existence will be able to fully align themselves with Gods will if they choose to. Naturally those who previously had aligned themselves to the extent possible in their imperfect past life will find it easier to conform to Gods plan during the 1000 year judgement day.
The Awake January 2010 had an article that explains JWs concepts on judgement day
What Is Judgment Day?
The Bible says that God “has set a day in which he purposes to judge the inhabited earth.” (Acts 17:31) For many people the prospect of being subjected to any kind of judgment is unwelcome. Is that how you feel?
IF SO, you can find comfort in the fact that Judgment Day is a loving arrangement that will bring great blessings to the human family—including those who have died. (Matthew 20:28; John 3:16) Why is Judgment Day necessary? What will actually occur during that “day”?
Judgment Day—Why Needed?
When God placed humans on the earth, he did not intend it to be merely a proving ground for future life in another realm. He created humans to live forever on the earth. Although physically and mentally perfect, the first human couple rebelled against God. As a result, they lost the prospect of eternal life for themselves and brought sin and death to all of their descendants.—Genesis 2:15-17; Romans 5:12.
Judgment Day will be a period of a thousand years during which humans will have the opportunity to regain what Adam and Eve lost. * Notice that Acts 17:31, quoted above, says that Judgment Day will affect those living on “the inhabited earth.” Those receiving favorable judgment will live on earth and will enjoy everlasting life in perfect conditions. (Revelation 21:3, 4) Thus, Judgment Day helps to accomplish God’s original purpose for humans and the earth.
God’s appointed Judge is Christ Jesus. The Bible says that Jesus will “judge the living and the dead.” (2 Timothy 4:1) Who are “the living” that will be judged? How will the dead come to life again on “the inhabited earth”?
Jesus Judges “the Living”
We are now nearing the foretold end of the present system of things, when God will destroy all elements of corrupt human society and remove the wicked. Survivors of this system’s end are “the living” who will be judged.—Revelation 7:9-14; 19:11-16.
During that period of judgment, which will last 1,000 years, Christ Jesus along with 144,000 men and women resurrected to life in heaven will rule over the earth. They will serve as kings and priests, administering the benefits of Jesus’ ransom sacrifice and progressively elevating faithful humans to physical and mental perfection.—Revelation 5:10; 14:1-4; 20:4-6.
During Judgment Day, Satan and the demons will be restrained from influencing human activity. (Revelation 20:1-3) However, at the end of Judgment Day, Satan will be allowed to test the loyalty of every human living. Those who remain loyal to God will have passed the test that Adam and Eve failed. They will be judged worthy of receiving everlasting life in the restored Paradise earth. Those who choose to rebel against God will be permanently destroyed, as will Satan and the demons.—Revelation 20:7-9.
Judging “the Dead”
The Bible says that during Judgment Day the dead will “rise up.” (Matthew 12:41) Jesus said that “the hour is coming in which all those in the memorial tombs will hear his voice and come out, those who did good things to a resurrection of life, those who practiced vile things to a resurrection of judgment.” (John 5:28, 29) This is not referring to disembodied souls of those who have died. The dead are totally unconscious and do not have a soul that survives death. (Ecclesiastes 9:5; John 11:11-14, 23, 24) Jesus will bring those asleep in death back to life again on earth.
Will the judgment of resurrected ones be based on what they did before their death? No. The Bible teaches that “he who has died has been acquitted from his sin.” (Romans 6:7) So, like those who survive the end of this system, those resurrected to life on earth will be judged “according to their deeds” during Judgment Day. (Revelation 20:12, 13) Depending on the final outcome of their actions, this will turn out to be either a resurrection that results in everlasting life or a resurrection that results in destruction. Many of those restored to life will for the first time come to know about Jehovah God and his requirements for life. They will have the opportunity to live in harmony with God’s will and receive everlasting life on earth.
No Reason for Fear
Judgment Day will be not only a time of instruction from God but also a time for those alive to apply what they learn and enjoy the blessings that result. Just imagine your joy at being reunited with resurrected loved ones and growing to human perfection along with them!
Just imagine your joy at being reunited with resurrected loved ones
God will allow Satan to test the loyalty of human creatures at the end of Judgment Day. But there is no need to be anxious or fearful. By the end of Judgment Day, all living will be fully equipped to face this final test. Judgment Day will thus be a part of the accomplishment of God’s purpose to undo all the effects of the original rebellion against God in the garden of Eden.
So yes all persons resurrected will have a clean slate, as it were,with God. Their eternal salvation is based on how they are judged during the 1000 year judgement day and their successfully withstanding the final testing period when Satan is released for a short time at the end of judgement day.