Windows 7: Want to change the navigation buttons in folders?

I installed Uxstyle core successfully and was able to install the theme I wanted. However, Uxstyle core does not do things such as replace navigation buttons/start button. So I downloaded another program called Theme Manager which let's you load up the files provided with the theme you downloaded and install them.

My question is whether I can use this program to install only the explorerframe.dll file? I don't want to change anything but the navigation buttons. Will this work? I am also sort of apprehensive because I have heard from numerous people that messing with those files can really wreck your system if you do something wrong. It doesn't seem complicated but I know from experience how easy it is for something to go wrong! So would I just load the explorerframe.dll file into the program and that will replace all the navigation buttons?

I also made a system repair disc just now because I heard this would come in handy if something went wrong. Is that sufficient?

I would make a complete system image - use windows 7 inbuilt one if you have to, or (better ) the free versions of Macrium reflect, or Paragon Drive backup.

Not sure if that will be feasible. I have about 100+ gigs of stuff on my hard drive and my external hdd got fried so I would have no where to back all that stuff up to.

All I am trying to do is replace the explorerframe.dll, is it really that risky? What could really go wrong?

Always do a backup of the original system file before replacing it with a modded one. If you're worried about getting your system files corrupted, i suggest you to use this software.