I recently updated to windows 10 and wondering if i put my serverfiles on an external hard drive and transfer it to a new computer will it load my old character
If it's an update I think it's not really necessary to backup the files to a external HDD, however, if it's a clean Windows install just a backup is needed.
If you are using the .DAT version of the server you can transfer your 'saves' as long as you copy and paste the server folders to your external drive exactly like you had them on your computer!
If it's the MySQL version you will need to make a backup of your game database and restore it into another MySQL instalation once you finish installing your new OS.