This.Why would you think that an OS re-install would lower your temps?
Maybe if this was an OEM (pre-built) computer, you still had the OEM install of windows on there including all of the bundled bloatware. If some of that bloatware was running constantly in the background and using extra CPU resources, then perhaps a fresh install of Windows would lower your temperatures. But really that would be about getting rid of the bloatware, not about windows. Just open up Task Manager and keep an eye on what is using your CPU.