I uninstalled Update 3, downloaded Update 5, ran it, it installed successfully. It then immediately searched for updates and told me there was a new version of Update I must install in order for Update to work. I accepted, it then uninstalled Update 5 that I had just installed, then stopped working completely. It didn't install anything. How can I this thing installed?
Check for previous versions of Vaio Update in Programs and Features in Control Panel and uninstall. Check the Program Files/Sony folder and delete any Vaio Update subfolders, reboot and try loading again.
Check your security software and if necessary switch it off while the install is running, also clear out your temp folder as there may be files left over in there from previous installs causing a conflict.
I am having the same problem. My computer is a PCG-GRT390ZP with Windows XP Professional. I recently found the update on the eSupport website. Immediately after installing it said it would need to download an update. It uninstalled the version I had just installed, popped up the installer for the new version, then the installer exited unexpectedly (just disappeared, no errors or anything). I have tried clearing out any Vaio Update folders in Program Files/Sony, uninstalling all versions of Vaio Update via Add/Remove Programs, and disabling my antivirus software (I have McAfee VirusScan Enterprise 8.5). I still have the same problem.
Try going into msconfig and disabling the startup programs, reboot and try running it again as it seems there may be some process in the background that the install program is clashing with. Once your done you can check "Normal Startup" again and reboot.
If you are still having issues after this, contact Sony support and they will be happy to assist:
Still no luck. First I tried disabling all startup items and all services beginning with "McAfee." Then I tried disabling more things and eventually got to the point where I disabled all startup items and services except for networking. The same thing still happens.