How to Iterate random numbers until a different cell with a non-random value says "OK"

I am very new to VBA. Here us my problem.

I have four cells that include large random numbers. When those numbers have certain characteristics and relate appropriately to each other, another cell acknowledges that fact by displaying the number 1000.

Say cell B1 is the cell that will display the number 1000.

How can I write the code so that the spreadsheet will keep re-calculating until 1000 appears in B1 and then stop? I want a code that references only B1 and not the cells with random numbers. Is there a way to do this without VBA?

I entered it in the VBA. How do I activate it without pressing the f9 key repeatedly? In "Options" I have it set to automatic and 10000 iterations. When I click on f9, it appears to recalculate once. It does not keep going until B1 registers 1000. Sorry I'm so ignorant about these things.