Vista - Cannot start some programs

When I try to run some programs I get an error message that look something like this. (Translated from Norwegian)

"Cannot find P:\path\program.exe Check your spelling and try again"

This started a couple of days ago. And it only happens on some programs and not on others, When I log in as the superadministrator I have now problems at all.

I have Vista64

Can someone help me on what can be the problem

Dare I ask if you a couple of days ago used a registry cleaner?, or modified any registry keys or user accounts? Sounds like user file corruption if the programs in question still work properly under the built-in Admin Account, but not the User/Admin Account. You may have to uninstall/reinstall the programs in question under your User account to fix the issue, and stop using Registry Cleaners if you are using one. They are not able to distinguish between legitimate and unwanted entries, and more often than not cause file/program/Windows corruption, that will ultimately result in the need to completely reinstall Windows. As a rule of thumb, If you do not know what the function is of the entry/link the cleaner wants to 'clean', then do not allow it to 'clean' it.

Yes I did infact modifie the registry manually a couple of days before.

I had gotten some advice to change the default installation directory.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion

Se the following thread for details:
Standard installation path - Vista Help

I had changed the ProgramFilesDir and the ProgramFilesDir(x86) key.

It did not work, so after I had tried to install Google Earth I changed it back again. But then problems started.

I guess I should have taken a backup of the registry before I started, but unfortunately I did not do that.

I have tried to uninstall and install a program to see if that could help. But I still have the same problem

Pleas give me a hint on how to proceed.

read this- You may need to restore/repair User Account or Vista Install:

Delete/Reinstall User Account
User Account - Delete

Restore
System Recovery Options
http://www.vistax64.com/tutorials/76905-system-restore-how.html

Repair of Vista
How to repair/create a Vista Recovery disk for those Without a Vista Installation DVD

When you changed the install directory it is now pointing to the new one and cannot find the program files needed to run.
As suggested above a System Restore hopefully will get you back on track.