Can you elaborate a bit about the crash? What errors were you presented with? If you received a blue screen did you read through the information dispalyed and make note of any error codes? Can you boot into safe mode? If so, what information can you gather from the event logs? Have you recently installed any patches to the OS? Were they system or Exchange updates?
There are a million and one ways to crash a server so the more information you can offer the better chance you will have of getting an workable solution. Otherwise it’s a crap shoot.
If your plan is to rebuild from scratch as it sounds you may have attempted, after applying SP1 and confirming your system will boot properly, I would apply any additional patches one at a time rebooting after each deployment. When the server comes up refer to the event logs and see what information is presented. Record all errors and research each one and correct if possible before moving on. Though time consuming this method will help you identify whether your problem is software or hardware in nature.
If you get stuck post your errors and the steps you performed prior to getting an error so that readers have something firm to work with.