SMACK! leave out the INI for now. WINAMP.MSI is in C:\ i take it? Can you execute it alone? without /qb or /qn? if it runs, cancel it. execute it with this line msiexec.exe /i C:\Winamp.msi /qb Leave the quotes out for now, just see if that runs. If it does, try it without msiexec.exe. If it continues to work, add INI= either AFTER /qb or before, I suggest after, but I'm unsure. FYI - You're the ONLY one with this problem, so it's something you're doing wrong. Also, redownload the MSI, it's best you do