Restore problem

Hi first post here, I hope you can help.

We are running 8.1 on Windows 2003 server and have had a server crash
over the weekend. A virus is suspected - we maintain an app server on
someone else's network, though we do have anti-virus running, the
symptoms were worrying - so we had to wipe and reinstall the OS and all
programs. We had recovered the 8.1 folder and the data off the crashed
computer prior to the wipe, but the last good .backup file is a few days
older than that.

Are there step by step instructions on restoring from the folder itself
instead of a backup file? Is it even possible?

Thanks,

Keith