Laptop screen is flashing horizontal multicolored lines?

Apparently my laptop screen is flashing/flickering horizontal multicolored lines that only last for like one second. It just goes "boom" multicolored lines "boom" gone. It's barely noticeable (but sometimes it goes all over the screen) and it's not all that frequent. I'm assuming that it happens mostly when the video card is being used intensely or moderately (on games and youtube/streaming videos). The laptop is mainly used to play Minecraft, watch anime/youtube videos, and play visual novels.

So, I'm, assuming that either:
1. The graphic card is going faulty (it doesn't need to be updated as it's driver is pretty much never worked on anymore for updates).
2. Something is wrong with the diodes (but those light up the screen as along with the backlight so I'm pretty sure this isn't it).
3. Heat damage has caused wiring or something to become faulty and nearly non-repairable.

Some details are: The graphic card is integrated; it's a NVIDIA GeForce Go 7150M. I run a Vista Home Premium OS. The screen is about 17" wide by around 10" long. I have had this laptop for about 2 years and run registry fix scans on it and such every day to help speed it up and fix errors.

The horizontal lines flash (roughly) every 15 minutes or so and only occur for around 1 second. It started out as a few lines in the middle and is now almost all over the screen. The rate at which the problem occurs slightly becomes shorter as the long as the laptop runs. Also, I think there are some really tiny lines that flash real quick on the screen every now and then too (about the same rate as all of the lines at once. I think the amount of lines that flash on the screen vary/are at random.

Once I restarted my computer the lines stopped flashing. This happened about 2 weeks or so ago and now it's occurring again today on 10/21/2011.

So, does anyone have any idea why this is happening? Any suggestions? I'm pretty adept with computers (I know a lot but don't have much experience taking them apart or working with the BIOS, etc). I'm also quite short on money to get a new computer so I'm getting worried that I'll have to buy a new computer soon (probably a desktop).

I'll try hooking up an external monitor to the laptop (if that's possible and if I can get my hands on one that is compatible with the laptop's DVI slots). If you have any idea what is causing this and if you have any idea on how to solve this problem I'll greatly appreciate it!

It is possible that there is a loose ribbon cable in your laptop somewhere. It is also possible that the heat, or a shock has dislodged the heatsink and fan on the GPU. If it is neither of those double check your driver, and software for your graphics card

The software seems to run how it's supposed to and the driver should be OK. Just like what you said, it probably is caused by a shock or a loose ribbon cable. In my area, our power sometimes goes out for a few seconds and comes back on sometime late at night (3/4:00AM) and during thunderstorms our power sometimes also goes out and turns back on (power spikes?). Therefore, if it is a shock problem, then there isn't much I can do in fixing the shock-damaged hardware other than replacing it (which would cost a lot and be irritating so I would just have to buy a new computer). Speaking of the power going out, I think it went out sometime early in the morning the day before the problem happened again.

If the problem lies with a loose ribbon cable, that might be caused be me opening and closing my laptop's screen whenever I start it and turn it off (I run it every day all day and turn it off when I go to bed late at night). Other than shutting the screen when I'm going somewhere for half the day or longer and shutting it/opening it during the beginning of the day and before I go to bed, I don't mess around with it.

Either way, if the problem does not lie within a software problem and is more of a hardware problem, I'm pretty much screwed. Since the problem sometimes goes away when I restart the laptop, perhaps when I turn it on the video card doesn't get enough power due to damage from previous power spikes/etc. So when it is turned back on, it just so happens to get enough power the next time and the problem doesn't occur. There are so many probable reasons why this problem occurs that if it isn't a loose ribbon cable, then I should just wait until the problem gets so bad that the laptop has to be set up with an external monitor or considered useless/for scraps.

Anyway, thanks for the feedback! My laptop's CD-drive and Wireless adapter have also kicked the bucket so I shouldn't be surprised that another crucial part (the screen or video card) is going dead too. Running computers all day and having power spikes damages the hardware and when you have that for 2 years, it's no wonder the laptop is showing signs of failure (if it were a desktop the problem could be easily solved).

If it was electrical damage, you'd just have a broken power port and a bricked battery or the entire thing would be gone. Aside from that, when it does happen, your wall socket/powerbar socket will turn black and melt.
If you keep your laptop on a desk and it does that, chance are, it's not the ribbon cable.
Artefacts like this generally happen from a dying chipset, or an overheating one. Go clean your laptop out, fans, heatsink and apply new thermal paste.

I put my money on your video card going faulty, clean the entire thing and hope that it goes away, nvdia m 9xxx series are very delicated, I know cuz i had a m 9750gtx and it went faulty after 3 years or less.

OK. I had my laptop cleaned out with compressed air and even removed the bottom panels and blew off any dust/etc off the hardware that was apparent after removing the panels (memory, HDD, and an extra space). I started it up and at first the laptop made a whirring noise and when it got to my desktop my computer wanted to install my mouse's driver again for some reason (probably because I removed the battery before cleaning out the laptop). After it installed the driver I was prompted to restart the computer so I did. No whirring noise happened after that (I think).

So yeah, I don't know if the line problem will happen again but if it does, I'll know that it's probably because of the video card going faulty.

Thanks for the info everyone! ^_^

Just throwing it out there for curiosity, did you ever get around to using an external monitor to help isolate the problem to either the laptop's lcd or it's gpu?

Nah. I didn't have the money, space, nor time to go buy and hook up an external monitor that is compatible to it. The problem went away and probably won't return for a while (my guess). Like said above, the problem was probably caused by overheating so I cleaned out my laptop just in case.