i downloaded the demo of mass effect 3.installed it. i get a message that the physics something didnt initialise.and then it asks me to get the latest version. reinstalled since the physx drivers provided with the demo where allready the latest(also tried earlier versions).the installation didnt happen. after hours of browsing through the web i tried installing after using the driver swiper and then the windows installer cleaner and then installing physx with the "/quiet" line added so as to force install it.cant know if the install ever happened.checked in control panel and some times the program was there and other times it wasnt. tried the things mentioned above while rebooting.many times with different sequences.then installed the demo again and again.we're talking about 6 hours straight without getting any resolts. nothing happened.and im freaking out cause i really dont care about the demo but what will happen tomorrow that im gonna go get the actuall game?i still remember the same issues i had with ME2 and physx.but this time physx just doesnt want to be installed!its like windows installer got something personal with physx.it feels like my pc is possessed. this has happened before.with other games and it usually happens with other installations of other software.but this time it hurts a lot.cant recall how i solved the problem in the past.maybe something else was wrong. last resort option is a complete format of the pc.but im not gonna just do that without hearing anything from you guys.any help will be appreciated. the only thing i didnt try so far is to turn off my antivirus.will do that too but i dont expect any changes. please dont ask about hardware cause its irrelevant.windows 7 home premium.radeon hd.all software updated. any ideas will be greatly appreciated ^_^ PS:whenever i double click on the application to start the physx install a few little windows pop up and then instantly dissappear.and at the same time in the task manager on the processes tab appear 2 processes named "msiexec.exe" for each try.