With Loop + Find Method And Sum The Negative Values

I have a very large worksheet (row count maxed in 2007, and then some), for which I need to do the following: search column A for a string that will occur many times, and then check the 10 cells that follow in its row for negative values, dropping some sort of indicator in the 11th (shading it red or something would be fine). An additional bonus would be if the 10 cells that possibly contain a negative could be summed (the sum could serve as the indicator?). If no negative is found, nothing need be done, and the macro should chug along searching A for the next reference to this string.

My hope was to do a sort of "With Range("A:A"), .Find("MyString")", save position as StartPos, do the 10-cell row checking in a nested IF or For (though the For would take a long while, checking each cell individually), then doing a .FindNext after StartPos until = StartPos (does .FindNext loop back to the top?). The formatting of the indicator cell in the 12th cell in each relevant row doesn't really matter, it's more just for jumping to critical rows.