I had this issue a while ago, if I'm not very wrong this is due to VirtualBox ... it times out trying to find the VM and then Vagrant assumes there's none and just creates a new one.
But I'm not 100% sure on the facts :)
Still the solution is to check your "C:\Users\{user}\VirtualBox VMs" folder (where VirtualBox saves them) ... depending on your usage you might have multuple subfolders so pick the folder that looks to be correct (look for the date modified and name).
In that folder you'll find an xml file named {vm_name}.vbox-prev. Open the file and look for (should be line 9) <Machine uuid="{_some_id_}".
Copy that id and go to your project folder (where you're doing vagrant up) and open .vagrant\machines\default\virtualbox\id, you'll find an id there and if it's different just replace it.
Cheers,
Bogdan