Reformat and reinstall of NT4 and Exchan

I need to reformat and reinstall NT4 and Exchange. I have a system with four hard drives each divided into partitions (which I did through NT’s Disk Manager Utility). If I reformat only my O/S drive (which has a partition for NT O/S and a partition for Exchange), will my other drives partitions and labels still be recognized or am I going to have to start from scratch on all of them? I’m reformatting to change the server from a PDC to a BDC. Thank you.