Lag Waves 2: The Cause

I've been in denial way too long now, but enough is enough. My computer... has lag waves.

Your mind says, "OK, so what?"

Well, the thing is, my computer didn't used to have lag waves at all. But now I'm starting to get them in certain games. Earlier I've stated that I thought overheating and a semi-broken fan was the cause, but somebody (I can't remember who) stated that a broken fan can't cause lag. The reason I thought a broken fan could cause lag, was because, back when I had my old laptop, it experienced a lag wave glitch, and when I sent it in for repair, the repair records came back stating that they fixed the fan. After that, the lag waves stop.

In my old laptop, when it had the lag wave glitch, it stopped me from being able to reinstall the OS, because it would shut down randomly in the middle of installation. It wouldn't reinstall until after I sent the computer in for repairs. I don't know if this same thing will happen with my new laptop or not, because I haven't tried reinstalling the OS yet. Reinstalling a Vista OS is new to me, and I'm sort of afraid to do it. I also hate having to back up everything.

The lag wave glitch often happens during Counter Strike: Source. It can't be an issue with the server though, because I play it off PacSteam, alone, with AI units. Runescape also has the lag wave glitch apparently. But I doubt that's a server issue with Jagex, because it didn't used to do that when I first got this laptop.

So it comes down to this:

The only evidence lead I have to the cause of the lag wave glitch, is the repair report from my old laptop, stating that the fan was broken. But if the fan didn't cause the lag wave glitch, what did? And what's causing it with the new laptop now?

I know nothing of computers, but did you try the basic? Virus scans, and what not.

what king of laptops are these? Updated video drivers?

I don't recommend playing games on laptop's unless its one of them overpriced gaming laptops.

Did you even try using google?

1.Fix Fan
2.Update everything
3.Take some diuretics
4.?
5.Profit!

Tried defragmenting?

BOE:
-Scanned my system thoroughly for viruses and spyware.
Nouman:
-I'm afraid I can't not play games on this computer. It's even more powerful than my desktop, and some of my PC games cannot work on my regular desktop. This computer should be fine though. It can run Oblivion in high detail without even trying. That may not seem like much compared to the kind of stuff some of you guys' computers can do, but it should mean something when it comes to the games that I play.
-As for video drives, I'll check the site for updates. It just seems kinda weird that the games ran perfectly fine the way the computer was but now they don't, and I haven't changed anything. This concerns me.
HaloOfTheSun:
-Yup Halo, I sure did. Nobody seemed to have the very same issue I was experiencing, and those who did, solved it with methods that didn't work when I tried them. So they had the same problem, but not the same source.
ahref:
-Fan seems to be working fine. But I'll blow in it and see if there's any way to get into the inside and clean it with a brush or something.
-Updates, will do.
-Taking diuretics will only distract me, and I need to conserve them.
-?
-Profit you say? Well if I fix it on my own instead of sending it in, that will save me a lot of time. Time is money, so yeah, I guess I could call it profit.
Leventhan:
Will do.

COmputer speed can be affected by the dust inside the cover. Try cleaning that

One issue could be your graphics card? Coz lag is caused by poor refresh rate. So either your graphics card is wearing out or a error with the motherboard.