It always take a long time for me to exit out of oblivion. Sometimes it can take anywhere between 5-10 minutes. It just shows the menu background and plays the backround music while apearing to do nothing until, after a few minutes, it returns to my desktop. Sometimes it takes a REALLY long time and then a window will pop up saying that "an error has occured and oblivion must close, we are sorry for the inconvenience." The game itself plays fine, it's just trying to exit that it has issues with. As I only realy exit the game when I'm done playing and it doesn't seem to have any kind of affect on the game itself, this isn't realy a huge problem for me, just a minor annoyance. I would still like to know if this is normal and why this happens. It would be cool if I could stop it from happening but it's not a big deal.

If you need to know, this is what it says in my "System properties" window:
Windows XP Home edition, Service Pack 3
1.61 GHz ADM Athlon processor 2650e
896MB of RAM

I think I'm using:
NVIDIA GeForce 6150SE nForce 430

I think that really svcks but I'm not sure ("Wal-mart special" as my dad would have said.) I don't know anywhere near as much about computers as I'd like to think I do.

And i'm only using Shivering isles and Knights of the Nine Plug-ins (GotY version.)

Normally this happens when you have a lot of mods installed, so it's a bit strange in that case. The crash on exit is very common though.

There is a solution however , an OBSE plugin called http://www.tesnexus.com/downloads/file.php?id=22410. It needs OBSE though. I used to have the same problem (with 200 mods), and it worked wonders, now the game quits instantly.

If you don't want to install OBSE, you can always try typing qqq in the console.

i know a way press ~ in game and put in qqq that should help but rember to save before you do this

It would be a lot faster if you had more RAM. Oblivion uses a LOT, and with less than 1GB of RAM, your Operating System (windows XP in your case) will have to save to the page file in order to give Oblivion the memory it requires. This ends up making it take a loooong time to load back after you close Oblivion.

By the way, your computer is really REALLY pushing the minimum requirements.