I think you probably mean how to stop it scanning on Startup? It would be a bad idea not to have it resident. To stop it scanning, double click the icon in the task bar (Or start AVG from the menu, if you have no icon) Right click the scheduler and then scheduled tasks. Then "Edit" the schedule as you wish.
There are many valid reasons for files to show changed, a Windows update, file system check that replaced them if corrupted, and others. As long as AVG doesn't say they are infected it is ok.
If you installed updates recently or installed other applications that can change the System files a bit, so it is normal. There was an update a few days ago that DID update that file, so you're ok. It had to do w/ fixing issues related to the TZ (time zone) environment variable.
You could also have a look at Grisoft's page and see if there is a later version for download of AvgFree.
Edited by uhaligani, 19 March 2007 - 04:39 AM.