Installer starts for nonexisting program

Two thoughts on this:
1) I remember there being a fix for Windows Installer in Win2K Service Pack 1. So, make sure you are running the service pack. Since SP2 is out, use that.
2) YOu can turn on Windows Installer logging to see what it is doing and why.
The following is from Technet article Q223300:
"Open the registry with Regedt32.exe and create the following path and keys:
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer
Reg_SZ: Logging
Value: voicewarmup
The letters in the value field can be in any order. Each letter turns on a different logging mode. Each letter's actual function is as follows for MSI version 1.1:
i - Status messages
w - Non-fatal warnings
e - All error messages
a - Start up of actions
r - Action-specific records
u - User requests
c - Initial UI parameters
m - Out-of-memory or fatal exit information
o - Out-of-disk-space messages
p - Terminal properties
v - Verbose output
+ - Append to existing file
! - Flush each line to the log

"*" - Wildcard, log all information except for the v option. To include the v option, specify "/l*v". "

Here is the URL to the article:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q223300
(please remove any spaces)

Hope this helps.