Check out this link for info on system restore:

http://vil.nai.com/vil/SystemHelpDocs/DisableSysRestore.htm

You can also get information on system restore by opening the windows help file and search for system restore.

The file is safe in the chest but you can delete it if you wish.

When you disable sys restore, it deletes files withing the restore point files. Having disabled sys restore, reboot and scan again with avast and if clear enable sys restore.

HTH David