Hi MalloryJ
What you are seeing are not files - these are just 'shortcuts' - right click and delete each one. Probably all to the same file caused by restoring your file - an old shortcut no longer work when you restore a file online.
Next time you what to access your file, use the Open link - this will show you how many actual files you have, whether in your Library or Online. Opening a file this way will create a new shortcut.
Having lots of files will not slow down your system, unless they are all open. If your system is slow it is more likely due to the size of the file. Check the copy in your local library to see how big it is. A large file will definitely slow down processing. If it is large (over 500 MB) it might be worth getting old transactions purged from the file. This will reduce the file size and speed up processing and report generation times.
Regards
Gavin