Having some issues with MS installer/uninstaller.

So I am trying to upgrade silverlight to the newest version, and each time I try it keeps giving me a error about silverlight.msi being missing and it won't install the newer version OR let me uninstall the older one. I even tried redownloading the same version and extracting the .exe to get the .msi package but even then it says its the wrong one. How can I bypass this so I can install this update? I've also had this issue with other installs that used the windows/ms installer. This has been a ongoing issue for a while on my pc its just never really gotten on my nerves this much.

Is there someway I can trick ms installer into thinking silverlight is not installed so I can just overwrite the files with the newest version and bypass the ms installer's uninstall of the old one entirely?

Thanks all. This issue is really getting on my nerves.