Changing Start-Programs menu from Window

I have Windows98 Second Edition installed on my computer. One day suddenly I found that my Start>Programs Menu has changed Windows95 style(side by side columns)filling up almost all my monitor screen from the normal Windows98 style(Single column scrolling) type. I have searched the net to find how to change it back to Windows98 style, but failed.

Can anybody to tell me as to how to change it back to Windows 98 style?