Today I got the arguments backwards when issuing
xcopy. This caused my source folder to be overwritten.
The system is Windows 2003 with standard NTFS. No special backup solutions running.
Is there any way to recover those files?
Unlikely. It's pretty likely that the copied files are using the same physical hard drive clusters as the old files, and the data is just gone.
On a journaling file system there might be a higher chance of recovering data. In general though this is a good reason to use backups and source control.