My Z61t refuses go to sleep mode

[Diehard]

Hello everyone!

I just bought an used Z61t. Its original OS was XP Pro, but has been ungraded to Vista Ultimate. I have some problem with it now

1) Using Power through AC Adapter, the laptop refuses to sleep when I press Fn+F4 or sleep of Vista. LCD went black, Hard drive off.. Then 1 second later the hard driver's on. LCD's still black but not in sleep mode. If I remove the mouse, the Laptop will ask me password just like screen saver mode.
It never happens when using Battery!

2) I was surfing web. Then, I can not visit other websites than Google (Problem loading page :Server not found error). Even though the Local net is still working. I have to plug it out and in back so I can visit other websites. I'm using Firefox and IE, it happens to both.

Is it normal for Vista if it uses 550 to 600+ MBRam?

Hope you guys can help me out!

Thanks

[Skywing]

I had this same issue, its due to your external mouse waking the system. Go to device manager and find that mouse in the list, right click it and go to Properties. Go to the last tab, it should be power management and uncheck allow this device to wake the computer.