My PC has been running rather slow in recent months, regularly hanging from a single mouse click, etc. I run Windows 7 Home Premium 64bit and I have run (and continue to run daily) many, many scans for virii/malware/spyware/rootkits/etc, but I've come to the conclusion that it's simply an old tired system that has been the same single installation for far too long, with far too many installs and partial uninstalls (lots of programs leave little bits behind) and I really need to just do a fresh install.

I currently have a fully up to date version of FFXIV installed and it works perfectly fine (aside from the issues that plague the entire system, but even those aren't as bad in the game). I would like to have the same in the fresh install of Windows 7 Home Premium 64bit. I do not want to download patches for the game over the 24 hours following the probably long and painful process I'll have already gone through getting the OS back up and everything else installed when I've already downloaded all the patches and things earlier. I'm also under the impression that some game data is stored client side, including gear sets and maybe hotbars and macros (?), and don't want to do all of those things from scratch either.

As such, I need to know what I should do to preserve the data I currently have, before wiping the drive. What files are hidden where and can they just be copied onto an external drive until the game is reinstalled and then pasted back into their original C drive locations?