If cell A2 shows TRUE and cell B2 = cell B1 then highlight cell C2 red.
If cell A2 shows TRUE and cell B2 = cell B1 then highlight cell C2 red.
Use this formula:
=AND(A2=TRUE,B1=B2)
Select cell C2 and go to:
Conditional formatting > New Rule > Use a formula to determine which cells to format > and input the above formula and then click the Format button in that window to choose how to format the cell when the formula evaluates to TRUE.
You can do that with conditional formatting. Look up Excel help for step-by-step instructions.