Well the processes may have rolled back by now, 3 days on from the posting. If not then I think you will have to stop & start the SQL Server Service. On restart the db will go into recovery mode but it should be OK several minutes later. Back the database up before the reboot and schedule a dbcc checkdb & possibly dbreindex for a quiet time afterwards.

Your description of the symptoms - no I/O but lots of CPU - indicate the processes are just 'spinning' and not writing data so I think the recovery will be quick.

This has always worked for me but, as other posters say, it's rare.