Chances are you have a registry entry which keeps calling the ms-installer (hense .msi) installer program.
Get Ccleaner (CCleaner - Home) and commit a neatness on your computer. Use the registry cleaner tool to clean the registry, but in that tool, use the startup application to see what all starts with your computer. I'm thinking you'll find a reference for the installer in there. You can disable or delete it. Use Disable to test and delete once you're sure.
Of course, use the registry backup tool before you clean the registry.

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I'm here, you may now make your next two wishes.

Beat Me, Whip Me, Make Me Use Windows!!

Every Piece of Electronic Equipment runs on a finite amount of smoke. The systems are normally very efficient at reclaiming the smoke and recycling it, however, should you do something to let the smoke out, your system will become useless.

SAVE THE SMOKE !!

New PC :
New: Phenom 9500 Quad 2.2, 4gb ram XP Pro 64-bit (Sata 0), XP Pro 32 bit (sata 1), 40 eide HDD (music), Pioneer Blu-Ray Burner, HP Multidisk CD-RW/DVD-Rom, 2x250 Seagate HDD's, ATI Radeon 3870, Asus M3A32-MVP Deluxe WiFi-AP

Old PC:
P4 1.5GHz, 768 Ram, hda-80Gb (80Ubuntu), DVD R/RW