i get this same error message when i double click the computer icon or any icon on my desktop.
I will say that if Jack's suggestion doens't work,, then I wouldn't mess around anymore.
Backup what data you can to an exteranl Hard Drive and Start from scratch.
I you are having the problem that I quoted. You have bigger problems than a simple take ownership will fix.
Please be careful when using TakeOwn, it's a very powerful tool that can result in these types of problems that are not easy to back out of. TakeOwn should not be used lightly, or for the hell of it. It should be used by those who know what they are doing, or those who aren't afraid of starting over from scratch. It should only be used when absolutely needed, and there are not many,,, extremely few times where it is actually needed.
Personally,, I suggest biting the bullet and Nuke and Reload.
The reason is,, if you can't open Computer from the desktop, then there is no telling what other problems have arisen that you wil spend more time trying to find and fix, and eventually have an unstable system you are going to ahve to reload anyway.