Попробуйте это
Sub backgroundcolor()
Dim color As String
color = InputBox("Enter color")
If color = "" Then Exit Sub
sColorsNameArr = Array("Black","White","Red","BrightGreen","Blue","Yellow","Pink","Turquoise","DarkRed","Green","DarkBlue","DarkYellow","Violet","Teal","Gray25","Gray50","PowderBlue","Plum","Cream","LightTurquoise","DarkPurple","Salmon","NavyBlue","LightLavender","DarkBlue2","Pink2","Yellow2","Turquoise2","Violet2","DarkRed2","Teal2","Blue2","SkyBlue","LightTurquoise2","LightGreen","LightYellow","PaleBlue","Rose","Lavender","Tan","LightBlue","Aqua","Lime","Gold","LightOrange","Orange","BlueGray","Gray40","DarkTeal","SeaGreen","DarkGreen","OliveGreen","Brown","Plum2","Indigo","Gray80") ' all 56 colors
pos = Application.Match(color, sColorsNameArr, False)
If Not IsError(pos) Then
Range("A1:B5").Interior.ColorIndex = pos
Else
MsgBox color & " not found!"
End If
End Sub