I'd be able to help you if it was RCT3, but I don't have a solution for this.

i would like to buy rct 3 for my advent netbook but i cant find anywhere to by it on a usb.
do you have any solutions for me

Instead of Steam, I bought a copy from GOG. I highly recommend this, as it is DRM-free (DRM is evil! ), it doesn't require installation of a download client, and they often add patches and fixes to old games so that they run better on newer versions of Windows.

I doubt that RAM is a problem for RCT3. Actually, I'm currently running RCT3 on an old 2001 Dell with a 1.5 GHz Pentium 4, 512 MB of RAM, Nvidia GeForce2 GPU, and Windows 98. It runs fine on the default settings, though I may upgrade the GPU to something newer.

Mate it seems that you met a similar  question as mine? Sorry to bother but my PC, an Dell Aline laptop has no DVD/CD drive as well. I want to play DVDs I bought from Amazon last year. I have no idea how to do it. I see from this article http://www.videoconverterfactory.com/tip...aptop.html, it gave two ways, the first is to buy external DVD drive. But I think it is too expensive which will cost me 15 dollars, and the other is to rip DVD to MP4? I am not sure whether this is legal or not? Do you know? In this thread http://www.pcworld.com/article/2020963/h...ows-8.html, It mentioned to install VLC, but it is just a player not a drive, i have no idea what it is talking about.
Along with my PC gaming discs, I do not know how to deal with them. Is there any way to convert those games into USB?

You can't convert a CD into a USB, that isn't a thing. The closest thing to that is actually something you mentioned; buying an external CD/DVD drive, which really is worth the investment if you plan on having that device long-term. Ripping CD's is legal so long as you aren't reproducing them or distributing them, although I doubt the police would come knocking on your door if you ripped a copy of RCT2 so you could play it (no one is that petty lol).

Just another option, you could always just keep the CD's as your collection, and then purchase a digital copy on Steam or GOG.

VLC is software required to run CDs and DVDs on operating systems like Windows 8 that aren't otherwise built with programs necessary to play these types of media. Since Windows 8 was built without a disc drive, naturally they also neglected to include software that can play a disc. In other words, if you buy an external disc drive and put a disc in, but you don't have a multimedia player installed like VLC or RealPlayer, there will be no indication on your computer that there is a disc in the external drive.

This is important to know so that you don't end up blaming the external hardware if the actual problem is a lack of necessary software. I thought mine was broken the first time I put in a disc, when I really just didn't have a program required to play it. Luckily, these programs are free, and if one doesn't work, another likely will.

Well I have windows 10 on one of my computers that used to have windows 7. And it reads the disks without needing special programs.