Computer's Start Menu Freezes, and...

[redsong]

My brother's computer has started acting weird today.

I've noted that:
The monitor doesn't register until the "Welcome" Screen.
The Start Menu freezes upon load and continues to say "Busy".
Anything that pops up with "Windows+<Key>" doesn't pop up.
"My Computers" files doesn't load. It shows the "Searching for..." icon.
Applications and folders including the Task Manager freezes.

[Carbon Dudeoxide]

Boot into Safe Mode and run a System Restore to a few days before the problem started.

[redsong]

The monitor doesn't register until after the Welcome screen.
It's blank/black, until the Welcome screen pops up.

Or rather, when we turn it on... the goes from green.. and then to yellow like nothing's happening.
Then it loads the Welcome screen. It doesn't show the 'boot' menu at all.

[Carbon Dudeoxide]

When you turn the computer on, keep pressing F8. See what happens.