Windows Vista 32 Ultimate

I have a default user account as administrator. No password. Took a while to
figure out, but when user account is turned on, Explorer (not Internet
Explorer) stops working. I get the following symptoms. Click on "Computer" in
Start Menu, and just hangs for minutes. Eventually get message that "windows
explorer not responding". If you close is down, not error number or other
message. When you go to Control Panel, it works at first, but eventually
system deteriorates and neither searching the drive or using Control Panel
will work. You can keep restarting Explorer from Task Menu, and sometimes
gain access to the Control Panel. With User Accounts tuned off, system works
flawlessly.