I have just bought a new Laptop with Win7 64bit. Recently I encountered some errors, which included not being able to save some files, Windows Installer errors and file extracting probs. I found out that they all were related to my %Temp% folder's permissions being set to read-only. I found out here that I had to set all permissions to Full Control, change ownership and add a "SYSTEM" named permissions holder. I did all these and no more errors. However some time later the probs came back. I checked the %Temp% Folder and again in was Read-Only and "SYSTEM" user was removed. Reverting these settings works but they keep changing back. I haven't been able to track down when these changes occur, but no luck. Also, I have used Win7 64bit and 32-bit on another PC and never had this prob, and come to think of it, first few days I didn't have it on my laptop either.