Upon startup, I get the Toahiba logo just like normal. HOWEVER, I have noticed that the blue loading bar is no longer there. Now after the TOSHIBA logo screen the screen just goes black and has a small WHITE line in the upper left corner. My computer was running perfectly fine until I decided to restart the computer just because I hadn't done it in a while. Any suggestions?It may be by your BIOS.
Try remove then insert a BIOS element. (It is in your motherboard).
Ignore the post above. Can you boot to safe mode?dear Alllan!!!!
If you remove your Bios element all your setting (Bios) have been defaults. After it he can log on windows and try go to safe mode.Ignore all posts by mustdie.My computer would SOMETIMES behave that way, nothing but a black screen with a blinking underscore in the corner. I found it only happened if I had accidentally left a flash drive plugged in at startup. Removing the flash drive and rebooting solved it.

Your problem might have some other cause, but try it without any extra hardware connected just in case. No CDs, no USBs, not printer, nothing but the essentials.