As previously mentioned above in the comments - and tested out myself:
This error is rather ambiguous. Therefore, you should check the error.log located at \xampp\apache\logs
When I had this issue, it was because Skype was already listening on port 80 & 445. I was able to get around this by exiting Skype, starting the Apache service, and then restarting Skype. You can check the current port listeners by opening a command prompt and typing Netstat -a
It is also recommended to have User Account Control OFF as it may block some features built into xxamp.
Prior to this though, I had an issue after I modified my Apache httpd.conf file. Reverting those changes (or reinstalling in the user's case) will resolve that issue.
File does not existDo the files exist or not? If not, you got your problem. If yes, they do exist, apache might not have the permissions to access the files.