Fill Now() formula if system date is greater then range value

hi,
i am using

Dim LValue As String
if range c1 = 0 then
LValue = Format(Date, "dd-mmm-yyyy")
Range("B1") = LValue
else end if

i want to add if system date is greater then b1 value then also run now()
like this

Dim LValue As String
if range c1 = 0 or if date > range b1 then
LValue = Format(Date, "dd-mmm-yyyy")
Range("B1") = LValue
else end if

thank you