A. From a command line, you can execute the new Microsoft Installer (Microsoft has renamed this application Windows Installer) with the msiexec.exe statement, which has several command line options:

/i \[package\] Installs the specified product
/f p|o|e|d|c|a|u|m|s|v p - Reinstalls a product only when a file is missing. 
  o - Reinstalls a product when a file is missing or an older version of a file is installed. 
e - Reinstalls a product when a file is missing or an equal or older version of a file is installed. 
d - Reinstalls a product when a file is missing or a different version of a file is installed. 
c - Reinstalls a product when a file is missing or the stored checksum value doesn't match the calculated value. 
a - Forces all files to be reinstalled. 
u - Rewrites all required user-specific registry entries. 
m - Rewrites all required computer-specific registry entries. 
s - Overwrites all existing shortcuts. 
v - Runs from the source file and recaches the local product.
/a \[package\] Installs a product on the network.
/x \[package\] Uninstalls a product.
/j u|m \[package\] Advertises a product (u is current user; m is all users).
/l i|w|e|a|r|u|c|m|p|v|+|!\[log file\] Specifies the log file and the options you can use.
  i - Status messages 
w - Non-fatal warnings 
e - All error messages 
a - Action startups 
r - Action-specific records 
u - User requests 
c - Initial User Interface (UI) parameters 
m - Out-of-memory 
p - Terminal properties 
v - Verbose output 
+ - Appends to the existing file 
! - Clears each line in the log file 
* - Wildcard. Logs all information, but the use of the v option isn't included. To include the v option, type "/l*v." 
/p \[patch\] Applies a patch. To patch an installed Administrator image, you should also use the /a switch (i.e., msiexec /p \[patch\] /a \[package\]). 
/q n/b/r/f Sets the user interface (UI) level.
    n - No UI
    b - Basic UI
    r - Reduced UI
    f - Full UI
/y   Calls system API DLLRegisterServer to register the module--e.g.,
      msiexec /y savill.dll
/z   Calls system API DLLRegisterServer to unregister a module--e.g.,
      msiexec /z savill.dll