I don't know about the over-heating. Is this laptop still under warranty?
As for the driver...
What ATI card do you have? Did you get the latest driver from ATI for your card? Do you know how to go get the latest driver for your card?
IF you answered YES to all these question, CONTINUE to read below.
IF you answered NO to any of these questions, DO NOT FOLLOW THE STEPS BELOW.
If you answered NO, to any questions, please post the info on your video card from your laptop. If you do not know how to obtain this info, post again here saying so.
Can you use windows at all? Can it boot normally sometimes? Do you have the internet on it?
If you have another PC where you can DL an ATI driver, do so and then save the downloaded file (DO NOT double click this file after download complete) it on a disk or flash drive. Then, put it in laptop and put the ati file on desktop.
If you can use windows on it, and have the internet, you can directly dl the file to the desktop. Make sure you save ti to desktop and not a previous location.
As windows boots up, press and HOLD F8 key (press it and hold it as soon as you can after boot begins). Use arrow keys on keyboard to select "Safe Mode".
Then see what happens. Windows should boot in a crappy resolution, but that's OK.
Go to "Add/Remove" programs in your control panel, and search for any ATI files. Then, remove then and restart.
Press and HOLD F8 during boot up to verify you're running in Normal Mode. If it's not on normal mode, use arrows to select "Normal".
After a window is done booting, double click the ati file you put on the desktop and let it run. This will install the new ati driver.
After the driver is finished installing, it should prompt you to restart. After that, everything should be fine.