1. Turn off your Toshiba NB255-N250. If the charger cord is plugged in, unplug it.
2. Remove the battery by first unlocking the switch labeled 1 and then sliding the switch labeled 2 while pulling out the battery from the back.
3. Discharge all power from your laptop by holding down the power button for 1-2 seconds.
4. Unscrew the screw shown in the picture (it will be hard to unscrew; it has threadlock) and pull the lid off of the memory bay. This may be tricky; try working your finger around the back and nudging it forward while pulling it out.
5. Slide over the two clips which are holding your RAM in place; Your RAM will pop up slightly. You can now gently remove it.
6. Take your new RAM and gently insert it the way you took it out, at a 45 degree angle; make sure it is all the way in. Then, push it downward, so it clips in.
7. Reinsert the memory bay cover, pressing evenly on both sides. Now you can screw the screw back in.
8. Put the battery back in, making sure to lock the switch labeled 1. You can now turn on your computer! You can check on your new RAM by opening the start menu, right-clicking Computer, and selecting Properties. Go to the section labeled System and look at your Installed memory (RAM). It should now display 2.00 GB! (Unless you are installing a different amount, but two gigabytes is the maximum recommended RAM upgrade for the Toshiba NB250-N255.)

If you need any more assistance, please leave a comment below.