I have windows xp which came installed on my dell dimension e510 desktop. The computer stars up ok and the log on screen appears with the five users listed as normal. But when anyone logs in not all the programs appear on the bottom task bar. The start button still appears but Zone Alarm and my net zero wireless icons among others do not load. The other icons still appear on the screen as usual, but if I try to access any programs by clicking the icons or through the star menu, I get the error message, "Windows cannot access the specified drive, path, or file. You may not have the appropriate permission to access this item." This started happening intermittently a couple weeks ago and rebooting did help, but now it is a permanent condition. I can access existing documents and photos but cannot open any programs, including help and support or any windows utilities.