I personally use K-Lite Mega Codec Pack as it has just about every audio & video codec known to man.
I would strongly advise against codec packs. Very strongly. Most Codec Packs incorporate too many conflicting codecs, usually have poor uninstallers, and invariably end up buggering up your codec chains. The more codecs installed will impact performance, and VFW stability.
So whilst codec packs are a one(ish) click solution, I'd fine tune your requirements and just install whats required.
I know what you're saying, but the K Lite installer is quite smart and only registers the codecs that your system is missing.
Any codecs that are installed are automatically registered so that any media player you have installed will play them, and other software (eg, Nero Burning ROM) will also take advantage of them if it needs to.
I will say that if the OP is going to install VLC Player then he (or she) should pay attention to the installer as it will install the Alot toolbar (among other things) by default.
I find the K-Lite one is particularly problematic, although in fairness, it is the most popular.
Even if it worked for everyone all the time, the more codecs installed, the more impact on performance. And any break in the codec chain will break VFW, so more codecs will increase the chances of this.
Hence, I prefer the more tuned approach. Although the advantage of the (older) MS/Windows platform is you are free to make your own choices

In this case, as its only a (quite old) laptop, not a full blown HTPC, most codecs probably aren't relevent anyway.