I unwisely installed the old remote agent (Backup Exec 10d) on a couple virtual 2008 servers and got the startup error associated with the vsp.sys file upon rebooting. I know this is an old issue, but this tip may help someone. Find a good server (2008) and install the agent just like you did on the one that will not start. Browse to the windows\sys32\drivers directory and copy the vsp.sys file to a location that you can use to import that file into the disabled machine through command prompt (using system recovery options). Once you copy the file to the appropriate location, use F8 to boot into windows boot options and choose "disable driver signing" or something to that effect. This will allow you to boot windows, log in, and use uninstallaaofo64 (or 32).cmd to clean the machine. DON'T FORGET TO USE THIS COMMAND ON THE MACHINE THAT WAS WORKING ALSO! Reboot again normally.