string.replace

Question

How come this doesn't work? string words = @".,[rootdirectory]\usr\%username%,[rootdirectory]\fastforward\pvs100,[rootdirectory]\fastforward\pvs100\obj,[rootdirectory]\fastforward\pvs100\src,[rootdirectory],[rootdirectory]\start\general,[rootdirectory]\fastforward\ffw100\obj,[rootdirectory]\fastforward\ffw100\src,[rootdirectory]\fastforward\ffw100\test,[rootdirectory]\realapplied\operations\opr300\obj,[rootdirectory]\realapplied\operations\opr300\src,[rootdirectory]\realapplied\operations\opr300\test" string dir = "n:\realsoftware" string dir2 = "[rootdirectory]"; words.Replace(dir2,dir); textBox1.Text=words; So i want to replace [rootdirectory] with n:\realsoftware What am i doing wrong? Thx in advance