Don't forget I said if avast finds an infected restore point it can move or delete only that restore point.
avast should be able to 'move' just the infected restore point to the chest and not all restore points.
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So there is no need to delete all or clean-up and leave only the most recently created one.
If you want to do this then try this - Create Clean Restore Point - Clear old Restore Points.
Create a clean System Restore point:
1. Click Start, All Programs, Accessories, System tools, System Restore.
2. In the pop-up that appears fill in the radio button to Create a Restore Point
3. Click NEXT
4. Enter a useful name that you will remember if you need to find this again (Clean Restore Point)
5. Click CREATE
You now have a clean restore point, you should clear the old ones:
1. Click Start, All Programs, Accessories, System tools, Disk Clean Up
2. Click OK on the C: drive
3. Click the More Options tab
4. In the System Restore section click the Clean Up button