I've got one, possibly two, problems at the moment.
A few months ago when I played Call of Duty 4: Modern Warfare on my laptop, the game would run fine. There wasn't any lagging/slow gameplay. All was well. However now if I go to run the game it's really really laggy to the point it just ruins the game. I don't think I've changed any of my settings since then so I don't understand why this is happening. I also haven't played the game online at all, always just as a single player.
The second problem is with the Assassin's Creed: Revelations game I've just received for Christmas. The game installed and will open up/load fine. I had no problems in getting everything sorted from that point of view. However as soon as I go to play the game itself, there is huge lag and the game is bascially unplayable.
I've tried generally cleaning up my laptop, getting rid of junk etc and I've also done a couple of defrags but still no difference to the running of the games.
I don't know a whole heap about the inner workings of computers so please excuse any "dumb" questions that may occur.
Here are the laptop specifications:
Intel Celeron Processor T3500
Windows 7 64-bit
Mobile Intel Graphics Media Accelerator 4500M
Generally, more modern games require a dedicated GPU, as personally I believe a Radeon 6570 would, but as you have a laptop you cannot interchange parts, I image particularly so on a Toshiba model.
Unfortunately, I doubt there is little you can do regarding your Assassins Creed Revalations FPS issue, as your processor is taking the strain for the graphic rendering as well as the physical processing, other than just decreasing the graphic settings to minimum and disabling unneeded options.
As for your COD4 lag, I would advise turning your settings down again, as your processor may just have some difficulty in certain parts of the game which are render heavy, as well as closing all other activities, and perhaps investing in an item such as TuneUp Utilities with its 'Turbo Mode', or finding something similar.