have installed Ubuntu 12.10 on laptop packardBell EasyNote TK Processor Intel Celeron T3500 Screen 15.6" 16:9 HD LED LCD
Thanks in advance for your advice!
Try starting Ubuntu with the following kernel parameters: nomodeset, noquiet, nosplash
Check this link if you need help settings the parameters (boot options): https://wiki.archlinux.org/index.php/Kernel_parameters#GRUB
nomodeset
is most important. It makes the kernel wait to initialize some video settings and use the more dependable but less capable BIOS video mode. This was described previously here.
noquiet
and nosplash
just turn off the splash screen so you can hopefully see the ugly startup text scroll by and catch any other possible reason for your issues.