If you use the default locations (as defined by Microsoft) for 32bit and 64bit applications,
Program Files (X86) and
Program Files respectively, then:
- the 32bit and 64bit versions will by default install into those locations and you will have a calibre2 folder in both,
- and you'll have two entries in Programs (Apps) and Features,
- and, if you use them, I assume you'll have two desktop icons
If you have both installed and you don't need the 32bit, then remove it via the Windows Control Panel or Settings applets.
BR