Welcome Eleanor, I'm afraid not. The best you can do is attach WinDbg noninvasively. With noninvasive debugging the target applications gets frozen and WinDbg is able to read and examine memory and various data structures. You cannot step through the application though. Check out WinDbg. From A to Z!
- "Invasive vs. Noninvasive Debugging and Attaching" at slide 16
I hope this helps,