Yes, that will uninstall Windows Messenger entirely. %windir%\inf\msmsgs.inf is the setup & configuration file, & you're calling its uninstall procedure.
If you want to just disable it & not actually delete its files, there are several methods to do that...here are my 3 favorites...
1.) If you're on WinXP Pro, there's a nice GUI method to disable it:
- Click Start -> Run, type Gpedit.msc & click OK
- Under the Computer Configuration category select Administrative Templates -> Windows Components -> Windows Messenger & locate the following 2 settings:
* 'Do not allow Windows Messenger to be run'
* 'Do not automatically start Windows Messenger initially'
- Double-click each one, select Enabled & click OK.
- Reboot your machine and all will be well in XP-land.
Alternatively, you can use one of the following methods:
2.) Rename the Windows Messenger exectuable, located at c:\program files\messenger\msmsgs.exe
3.) Click Start -> Run, type Regedit and click OK.
- The Registry editor program should open. Navigate to the following Key: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft
- Create a new key by selecting Edit -> New -> Key. Name the new Key: Messenger
- Select the newly created Messenger Key and create a subfolder within it named: Client (The key should look like the example below...)

- Next you need to create a DWORD value. Right-click the new Client key and select New -> DWORD.
- Name the DWORD: PreventRun
- Give it a data value of 1
- Restart WinXP & it should be disabled.