Did you not allow avast to send it to the chest (as it should be able to do that) ?
If you did, were there any errors on trying to move or delete it ?
That way you are only dealing with the single restore point and not loosing all restore points (Clean or otherwise) if you disable system restore.
- Infected Restore Points - There really is little benefit in chasing a detection in the system volume information folder. It is only there because it had previously been deleted or moved from the system folders and this is a back-up created by system restore.
- Worst case scenario it isn't infected and you delete it, you can't use that restore point in the future, not much of a loss and the older the restore point is the less of an issue it is.
- So if there is any suspicion about a restore point then it is best removed from the system volume information folder or it could bite you in the rear at some point in the future when you use system restore if it included that restore point.