VBA help - for loops/if/dropdown lists... big calcs...

[Derrick]

I want to make a macro that will create a dropdown list of steel members that
are acceptable. the easiest way to explain is with an example...
2 sheets: Verticals, Steel
Verticals:
A B C D E F
1 Deflection Steel
2 Allow Actual Needed Description Ix Weight
3 .5 .4 (dropdown1)
4 .32 .25 (dropdown2) 2X3 BAR 3 5
5 .5 1.3 (dropdown3) 4X3 BAR 6 8

Steel:
A B C D
1 Item Description Ix Weight
2 1 1X2 BAR 1 2
3 2 2X3 BAR 3 5
4 3 4X3 BAR 6 8

(Dropdown1)=
=-"NONE NEEDED"
(Dropdown2) =
=- "2 - 1X2 BAR"
=- "3 - 4X3 BAR"
and displays "2" when selected
(Dropdown3) =
=- "3 - 4X3 BAR"
and displays "3" when selected

ok. So the point of all this is to have a macro that will go through my
steel sheet after doing my calcs to see if the defl works with the properties
Ix & Weight.. and display a dropdown list in the "Steel Needed" column.
i was thinking something like this: (but i dont know VBA)

C3,C4,C5=

if Defl Actual> Defl Allowable then
for (x=1, to 'Last item on Steel sheet', x++)
'check defl with formula, using item 'x' properties
if 'defl with Steel' < Defl Allowable then
' add to dropdown list
end if
end loop
else Steel Needed = "No Steel Needed"
end if

next:
if item '3, for example' is selected then
display 3 in cell
end if

can anyone help? ive tried this before, and haven't gotten far.
thanks so much.