SQL Server 2008 service keeps crashing
As suggested by Aaron Bertrand, renaming the files was just enough to solve this problem:

Save your backup files (or mdf/ldf files if you don't bother taking backups), and then obliterate that instance. Install a new instance (preferably of a newer version) and then restore/attach your databases to the new instance.
Try renaming that mdf file it's complaining about (and probably the corresponding ldf file, too). I haven't seen this issue before but it may take some trial and error for such an ancient, out-of-support version. Does your pen testing thing mention SQL Server 2008 (which could just indicate when it was written), or explicitly require it? Seems odd to require a version that is FIVE major versions ago, no longer supported, and quickly declining in use. I would double check that you even need to be dealing with this.