I’ve seen a couple of WoW player mention that they’ve had to delete/change their WTF folder and/or delete old UI’s… How do you do this? 
I’m afraid to do this on my own because I dont want to screw up anything when it comes to my precious game!
And, what are the benefits of doing this?
For the UI mods, it’s best to delete your old ones and then copy in your new ones. Simply copying the new mod folder over the old one is risky, since it may leave remnants of the old UI. Those old remnants can cause strange bugs.
I’m not so sure about the WTF folder. Anyone know what it does?
All your macros and such are stored in the WTF folder. All of your Addons are stored in the Interface/Addons folder. This is usually the first thing that Blizzard support will suggest if you are have problems with WOW.
Personally, I’ve never done this. When I built my new machine several months ago, to avoid having to go through the pain of setting up my UI and macros again, I just copied the WTF and Addons folder to my new installation. I’ve heard that the entire folder is actually portable, but I didn’t see the point on trying to that much data over when a reinstallation wasn’t a whole lot slower.
FWIW, if you’re getting progressively more sluggish performance and/or lots of errors, it could be the result of bugs in some of those files or simply too much old stuff. IOW, removing those folders is pretty much as close as you can get to a brand new installation without actually removing and reinstalling WOW.
Edit: I forgot, the WTF folder holds other account specific information besides just macros, like realm and character information. All of that stuff, of course, gets rebuilt if missing when you first log in, it may just take a little longer for it to get the relevant information.
Read Blaster master=)
What you do is make a copy of WTF and rename it WTF1 or whatever, then delete the contents of WTF [giving you a backup if you need it.] That gives you no mods at all. Add mods to taste and stir.
If it turns out that you seriously miss an older form of a mod, you can selectively go in and add it back by dragging or copying the mod components you want back to the WTF file.
Hope that helps=)
[can you tell I used to be CS for MMORPGS=) ]
This is because of the new patch, 2.4, which makes changes to the interface and many custom UI mods will not work properly until updated.
As per the WoW Tech Support FAQ: rename or delete the Interface, WTF and Cache folders. The game will create the defaults it requires next time it runs, and you should check for updated versions of your UI mods before installing them.
Note that WTF also stores your UI settings (what’s up on FuBar, where the Omen threatmeter is on the screen, which nodes your Gatherer is set to show on the minimap).