microsoft outlook facing problem

after i read an e-mail from inbox, the particular e-mail will automatically deleted. and it won’t even stored in the “deleted item” folder. so i change the whole new hard drive and do a fresh installation again, but the problem still occur. i was wondering was the whole inbox infected by virus, because i did a backup for all of the e-mail message (outlook.pst file), and restore back after the clean installation. isn’t because of this the probelm still occur?