A Virus or screwed XP

I have a XP Home installed.
When booting into XP now I log in and I dont get the start bar at the bottom. What i do get though is the small line as if it is hidden or minimised. But I am unable to get this back. Pressing the “start” button does nothing. Also my network adapter (pcima wireless) seems to have been removed. Windows seems to work ok apart from these problems as far as i can tell. Anyone any ideas as the next step to make??