Until a few weeks ago I was running the following computer and I use it just for gaming: Win 7 64 Home Premium Asus P8P67 MB i5 2500k ocz vertex 2 60g-system drive WD 500 GD HDD 8 gigs of ram 2 evga gtx 560 ti in sli The system ran flawlessly. I changed the Motherboard to an Asus P8Z68 and used a different i5 2500k-everything else remained the same. I erased the SSD and did a clean install of Win 7. Loaded the mother board drivers, video drivers and intel rapid storage. The system boots up and appears to be working great. If I try and use windows update I get the error code 0xc80003fa. I have googled the error code and done everything that has been suggested to fix the issue and still nothing. I have done another clean install and get exactly the same result. Other issues I am having also: I noticed that windows defender would not start up-it just sat there trying and eventually timed out. I figure I would download MSE and put that in, but the MSE install eventually fails. At one point I figured I would just manually download the SP1 update and install it. That update fails. I figured maybe something was wrong with the install so I decided to use the Windows install disc and do an upgrade. The install checks online for updates and downloads an update that is 1028 then proceeds. The install continues until the part where it is transferring drivers and such and when it seems that it is almost complete, it fails and rolls the system back. On one install I used Avast antivirus Pro and it keeps getting deactivated also. I am running the system as the admin of course. I have checked and the windows update and install services are running. I have renamed the sofware dist folder. Windows is activated. I have spent many many hours with this and just can't seem to get the problem. Anybody have any suggestions?