Sleepwalker stays resident in memory and infects all executed or opened COM files. It marks infected files by setting their time stamp to 10:47 (time field is not visible with normal DOS DIR command).
Sleepwalker contains the following text:
Sleepwalker. (C) OPTUS 1993.
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.