The changes being done are quite minor, in case of indexing - all that does is puts all the files names/information in 1 spot so it is faster for searching for certain things (if you have indexing on).
As for changing the directory locations of folders - that depends. If the standard user created a folder - then can move it wherever they would like since they "own" the folder.
As for your app to monitor CPU temperatures - it may require some kind of system change, or access to a system file/folder which would require admin priviliges. Different programs react differently to standard and admin accounts. Some require passwords, while others will happily run without admin access.
Straight from the horses mouth:
http://windows.microsoft.com/en-US/windows7/Why-use-a-standard-user-account-instead-of-an-administrator-account
Why use a standard user account instead of an administrator account?
The standard account can help protect your computer by preventing users from making changes that affect everyone who uses the computer, such as deleting files that are required for the computer to work. We recommend creating a standard account for each user.
When you are logged on to Windows with a standard account, you can do almost anything that you can do with an administrator account, but if you want to do something that affects other users of the computer, such as installing software or changing security settings, Windows might ask you to provide a password for an administrator account.