Laptop Display Cleaner

I pulled my laptop apart to clean the keyboard and now the screen will not work?

I unscrewed my toshiba p105 laptop in an attempt to clean my keyboard, but could not figure out how to undo a screw in the middle of the board. After I screwed everything back together, the computer turns on and seems to work fine, but my screen will not display anything (it is just black like the power is off). This is the same on battery power and on electricity. What have I done?
Thanks

DUDE!!!! NEVER TAKE APART A LAPTOP TO CLEAN SOMETHING!!! IT CAN SEVERELY DAMAGE ELECTRONICS!!!!!
Anyway, sorry for the flame. I just wanted to get the point in. Unscrew your Laptop Keyboard again, and check if there is anything frayed, loose, or broken. If there is, then *try* to fix it, or bring it to your local PC store and have then fix it. I recommend not using Best Buy, they usually don’t know anything. If nothing is damaged, do the same thing, because I don’t know the specifics.

4 in 1 LCD Laptop Screen Monitor Cleaning Kit Cleaner – dinodirect