After pressing on need to restart by Pressing Ctrl-Alt-Delete

It sounds, from your description, like what's happening is that when you turn on your computer, it boots to a newer kernel (such as 2.6.35-30-generic), which fails for some reason, and then next time you boot (i.e., after you press Ctrl+Alt+Delete), it offers you a list of kernels to choose from since the last boot attempt failed.

What happens if you shut down your computer, then as you're starting it up, hold down the Shift key? Does that give you the menu where you select your kernel, without you having to press Ctrl+Alt+Delete? If so, then what options are you offered, and which ones work? When you select an option that doesn't work, what happens? (Does it just go to a black screen, or are there visible error messages, or does it show the Ubuntu logo, or what?) If it shows the Ubuntu logo, then when it does, press Escape (and if that fails, press F2)--that may show the status messages that are "behind" the splash screen.

Also, what is the exact make and model of your computer (or, if that is not applicable, what is the make and model of the motherboard). And what is the make and model of the video card?

Laptop model : Compaq Presario V2000

What happens if you shut down your computer, then as you're starting it up, hold down the Shift key? Does that give you the menu where you select your kernel, without you having to press Ctrl+Alt+Delete? If so, then what options are you offered, and which ones work? When you select an option that doesn't work, what happens? (Does it just go to a black screen, or are there visible error messages, or does it show the Ubuntu logo, or what?) If it shows the Ubuntu logo, then when it does, press Escape (and if that fails, press F2)--that may show the status messages that are "behind" the splash screen.

I had the problem solved by reinstalling Ubuntu 10.10