I got a Toshiba Satellite Pro 4300 recently and the BIOS has "Stretch LCD display" option, but the weird thing is, it still has black borders while the images are enlarged. I've no idea why it behaves like that. My games are at 800x600 or 640x480 res, both are 4:3 and the display res is 1024x768 also 4:3. Also the image is literally "stretched" and some texts are not in its original shape, i.e. main menu texts in Red Aler95 configured at 640x480 res. So don't expect too much from Toshiba laptop displays.

Old Laptops dont support other than native resolution, its just the way it is.
If you play games full screen it either is on native full screen or with borders.
These things aren't meant for gaming but for office like programs.
This changed around the win98 era.
Some support pixel doubling or bad stretching. But you will keep having borders.
If you really want to resolve this, connect an external more modern vga lcd or crt. If at all possible.

Update: Toshiba 2805-S603 is OK. the screen is 100% fit when enabling LCD display stretch. Also it acts like a real CRT, not as Satellite Pro 4300 with stretched bitmap style and text/fonts shape shifted.