Toshiba NB255-N245, I get a blank screen

Try this followind method to get rid of Black Screen Problems.

1 . Take out your Laptop Battery
2. Remove your AC Adaptor Cord, that's the wall power, remove it.
3. Now hold down the Power Button for 30 Seconds
4. Then Plug your Battery and Plug it on the wall power
5. Then Power ON your laptop

if problems persist dont forget to leave some comment to solve your problems.
And I'll post some another tips

Toshiba wavy lines in picture

It could be the problems is your drivers of video card (built-in) try to uninstall the previous driver then download a new driver. just go in google search engine and type toshiba video card drivers and look some options.

Toshiba Satellite X200-AA3 PC Notebook No Sound

Problem: system 32 Snd Vol.exe"-s have no any device.

Solution:

Press F2 or Del  to enter in your bios setup then reset all settings to factorydefaults
If problem exist just need to Re-Install your Windows Operating System
but before you need first to back-up your data

hope it works! :)