Flash Player 11 is driving me up the wall.

Hello,
Windows XP SP3 32 bit. IE8 & 2 user accounts with system admin permission. Flash Player 10 worked fine. We clear all temp files, internet history & cache. I have uninstalled all previous versions & tried to install the lateset version. When trying to download Flash Player 11 error msg vary between "general error" or "cannot update (filename)" or we do not have the necessary permission. Now it's telling me that it cannot be registered. When it works it will download on 1 user account but the 2nd a/c cannot access applications that need FP to run. older versions cannot be re installed. Tried all suggestions in the forum. Have been trying for a few weeks to figure it out but I'm now stuck. Please help.


Robbie