Ok, do you have Avast! installed? I would imagine so, if you are speaking of their screen saver scan. To answer your Q, it starts fresh every time the screen saver does. It does not pick up where it left off last time, whether you have rebooted or not.
This might arise a worry that the scan is never thorough or it never finishes. Good news is Avast! scans very fast, and you can make it faster. The path to this scans setting are: Open Avast!>>Scan Computer>>Scan Now>>Screen Saver Scan>>Settings
Here are some settings changes to the Screen Saver Scan that I recommend, you can apply the ones you wish:
1: Under "Performance", check the "Store Data About Scanned Files in the Persistent Cache". This will slow down the first scan, but speed up all scans that come after.
2: Also under "Performance", turn Scan Priority slider bar up to the max
3: Under "Sensitivity", Turn Heuristics slider up, and check "Scan for PUPs".
I just replaced my XP desktop with a Windows 7 desktop. It included Avast Screen Saver. My question: does this start from beginning each time the screen saver starts? Or, does it pick up where it left off?
Likewise, does it do the same when the PC is shut off and restarted?
I "searched" this subject and didn't come up with anything. I am posting here in the Newbies forum as I find answers are more civil when "dumb" questions are asked. Also, I have been away for a while and now that I have a new machine with a new operating system you may see me around more often.

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