How can I remove Trojan Horse?

Hi,

Hello there..good day! I just want to ask if how to remove a virus which is trojan virus..because it is infecting my computer and now all my files are all hidden..and I can't unhide them..I am using command prompt to access my files..I am using Eset NOD32 Anti Virus..but still the virus is existing!..hope you guys can help me with this problem!,..

Hoping,

Jenny