hey Roberto...
seems like it could be any number of things... and many good suggestions were included in this thread..
for my two cents~ i too had a problem similar to yours... my tray icon would dissapear, and double-clicking on the program icon would just give me an hour glass for about 10 seconds..and then dissapear.. this is what i did to resolve the problem...
As was recommended.. i too used the symclean utility which you can get
Here ~this is from Symantec's ftp site. In addition to this utitility you might want to try this one only after you have run Symclean..this utility is also from Symantec and can be found
Here . This utility is called the RNav.exe Norton Antivirus Cleanup Utility. Keep in mind..the Symclean is only to be used if your NAV was part of Norton System Works. If not, then just use the RNave.. Futher information on using these utilites can be found
Here
So anyway, after i ran Symclean (i have NSW) i then manually went through the registry (Regedit) from the run box and manually deleted all entries for Norton, Symantec, and System Works. Yes, it's kind of dangerous to do..but i feel comfortable working with the registry..you may not.. in any event ALWAYS BACK UP YOUR REGISTRY!!!.. once all entries were deleted.. i then manually searched for all folders pertaining to Norton. Which also included deleting the folder C:\Program Files\Common Files\Symantec Shared<-- Make sure that folder is deleted. Also, make sure that any Window's Installer files client side (will have an extension of .msi or .msp)removed from this folder C:\Windows\Installer- which might be hidden..if so, make sure you enable to "View hidden files". That part may be a bit time consuming, as i manually had to go through all of those files, double-clicking to launch to see what programs they would attempt to install..then removing any that dealt with NSW or NAV...
I then rebooted..and then performed a clean install without any programs running~ but my key difference was that i installed it to a different folder from the default .. make sure you attempt to do that. so if it defaults to c:\program files\nav, maybe change it to c:\nav or any other directory of your choice.
i rebooted again, and was able to get it up and running without a hitch.
If we take Black_Pride's approach,...also a great idea...! try utilizing the Klez removal utility which can be found
Here. Let that run and remove any entries that may be found..keep in mind..if there are any infected files.. you will probably have to reinstall any programs that those files pertained to..
Also mentioned i think, is any popup stopper which might be running in the background such as adshield, etc.. it might be too aggressive..best to temporarily disable it during this procedure..
Anyway, good luck, and let me know how you make out..
~n