You need every patch that comes out. It isn't an accessory it's something EA makes that is necessary to the running of your game.

About your first question, why on earth must you move to sims 3? Some people play sims 3, some play sims2, some play both, some even play sims 1. Find which one you like and play it. You won't be left behind, many people including myself prefer sims 2 because IMO it's the better game.

You could try deleting the neighbourhood manager file.
Did you have the store addition? Custom neighbourhoods won't show up if the store addition was installed before and isn't anymore.

Sorry, I hadn't noticed.


SenkoTwiik
If it is sucuROM that's the problem and you are going to play with the disk in, then you may need to uninstall any disk burning programs that are on your computer. Ours came with Roxio and we used it to put our kids photos on a disk. It was this (legal) programme that the FT patch disliked. So uninstalling any type of burning program and using the unofficial FT patch from MATY would also be another way to try. You will have sucuROM on your computer, but I believe it will be a less intensive form.  Again this is only if sucuROM is the problem. Many people never have trouble with it.

Could be a sucuRom problem. http://www.simprograms.com/658/securom-removal-tool-added/  Some people never have troubles with it, I’m one of the hundreds that had the game become  unplayable after installing the Free Time patch.  I have had two new computers since then and would not let sucuRom on either of them. After installing all my games (bought legally, I'm no pirate) I used the no disk crack to ensure sucuRom never gets on my computer again.

Added a link so you can read about what sucuRom can do to your computer. http://en.wikipedia.org/wiki/SecuROM

Did you delete the letter box? Or is there no letter box on the lot?
Never delete the letter box. It not only controls the bills but also the portals for things like the school bus. I know one time I had a lot which I wanted to be residential but it had no mail box so I tried grabbing a mail box from a blank lot, put it in the sims inventory and moved him to the lot I wanted him to live on to find he had disappeared. So I couldn't get to his inventory to place the letter box. So I know no letter box can mean no sims. If this is the case, move the sim back to the bin and place a buyable mail box. I'm not sure where the download is, but if you Google you will probably find it.

I think that is either from GOS or from a GOS member's blog.

I think I had a teen runaway once, a very long time ago. The only way they will run away is if they have a number of bad relationships with family members at the house they live in. Aspiration level doesn't matter, low teen aspiration just causes bin kicking, painting destroying and flower stomping. Run away teens should not be a constant problem unless you are actively making them hate their family.

I would not use the default installer, you could be installing sims, hacks and anything with that. Also it will dump your downloads in all together-a very bad idea. If you can't use CI, then I would not install any lots at all unless you know the person who uploaded it and they said it was cc free and clean. You should not be seeing any kind of Character package in a lot. Could be there is a remote control car or something of that nature, but then you would not expect there to be a lot of them. Getting rid of/deleting files won't hurt, keeping them in your game might.

Do you have SimPE? You can check to see if those are sims in there. If it were me, with all those other problems I would uninstall, reinstall and start of fresh and not let any content in that you not sure off. You should be able to download netframe work yourself.

What kind of file is it? Can you open it with Clean Installer and see what it contains? Sim 2 houses can contain sims, but if they do you should not install them as that can bork your game. If it's a house you will be able to select lot only in Clean Installer and that should be installed were and how CI says to. That is in CI it will be a Sims2TMP and it will go to the Teleport folder. The game reads it and converts it to a lot you will find in your lot bin. If you are really unsure as to what it is or even if it's a Sims 3 file, I would just get rid of it.

I have it downloaded, I could possibly upload it on a bare lot for you. If you used Clean Installer you could just grab the birthing chair and objects. Did you want all the objects? I think-not sure-that the last model came with heaps of babies and a bassinette and a few other items.

Sometimes you can get in and sometimes you can't. If you have the ID number you can get them off the exchange and convert them to odp files. I've grabbed and converted a few of my old updates and some other people’s tutorials.
http://wtsims.livejournal.com/39347.html There is one for Mac's and one for PC's.

I've never heard of Gossip Girl, but I thought you meant a creator going by that name. Helps to specify what you mean. I Googled and came up with these things on TSR. http://www.thesimsresource.com/downloads/browse/category/sims2-clothing/search/gossip%20girl/ So now I'm assuming it's some kind of series.

In the comments section she mentions adding term papers, but she hasn't done it yet.

I think you mean this: http://www.modthesims.info/download.php?t=416677 It only allows you to write novels.