Graphical glitches like this one are characteristic of underperforming graphics cards. When my drivers glitched out recently, my BIOS freaked out and defaulted to my integrated card. I had similar issues in just a few games. Also, as far as performance goes, you should be getting more than 30 FPS with that processor. I have and i5 quad core, and it gives me a solid 70 when it starts to chug. This also points to a lack of processing power in your graphics card. Since you have an HP, you're in luck. You should be able to change out the graphics card for $150(? not too familiar with mobile cards) or so, instead of replacing the whole computer. If you absolutely cannot afford a graphics card upgrade, you may investigate a upsampling tool such as GeDoSaTo. It's advertised as a downsampling tool, but it works the other way too, and is specifically compatible with Divinity: Original Sin. If you need more help past that, let me know, and I'll do some experimenting to see if I can get DOS2 running in DX8.
