This sounds like the Customize button misses and in order to restore it, you will need to modify some settings in the registry with my help. Always make a back-up because editing the registry without a minimum of knowledge may affect your operating system, thus, making it unusable.
Start > Run > type regedit
- Navigate on the left to these locations, one by one: HKEYCURRENTUSER \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies \ Explorer & HKEYLOCALMACHINE \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies \ Explorer
- In the right panel delete the following keys: NoBandCustomize & NoToolbarCustomize
Now the ability to customize your toolbars will be restored. A restart is recommended, though.