How do I get the file bar on my pc?

Where is the file button missing from?
Did this problem recently start? Did it work normally before?

I think maybe you could try system restore to set the computer back to a time before the problem started
click start, click programs, click accessories, click system tools, click system restore
check the box: restore my system to an earlier time, click next
pick a bold date on the calendar, a date before the problem started
follow through with the directions.