What to do with Previous System Folders?

Question

First of all, Happy New Year to all!
I just spent two days doing an "Archive and Install" on my iMac at the advice of an Apple Genius who checked out my iMac at the Apple store. He said my iMac was running very slow but couldn't find any reason for it.
The first "Archive and Install" took six hours on the 30th, and then it was several more hours to get the software back up to speed with all of the updates. But after all of that, my system ended up in the Kernal Panic screen on start up. So today I got on the phone with Apple Care and they had me boot up with the Leopard Install DVD in the drive, holding down the C key. That worked, but I was back to square one with my Archive and Install.
The second try yesterday took another 6 hours, and then it took several hours to get my software back up to speed again. The Apple Care guy told me the Install should only take an hour, so that right there tells me something isn't right. Anyway, here I am after two very long days, with my iMac at least functioning again, albeit not faster as I had hoped. It's still running slow as molasses. This post has taken me forever to write due to only being able to type three or four letters, then wait for SBOD to stop spinning, then another two or three letters. It's so frustrating.
But, my main reason for posting here is to ask two questions.
1. The two "Archive and Installs" left me with two "Previous System Folders" on my hard drive that are almost 21 GB's!! I had 74 GB's free before and now have only 53. Can I dump those folders and get my space back? I sure hope so. If so, how do I safely do it?
2. The three folders on my dock at the right end; Applications, Documents, and Downloads, used to be in nice neat folders with symbols on them indicating what they are, but now they're just plain folders with stuff sticking out of the top of them, and in the case of the Applications folder, the Address book app is sitting on top of the folder, rather than inside of it, and all I see is the Address book icon, not the folder. How do I get those folders back to normal? I hate the way they look now!
I'm very frustrated that I'm having all of these problems with my iMac, but grateful at this point that I extended my warranty before the first year was up. I'm definitely going to have to take it back in for more help. I don't think it should take four minutes for iTunes to start up and shut down, four minutes for iPhoto to shut down, or two minutes for a photo to open up in iPhoto after clicking on it, etc., etc. I have the Spinning Beach Ball of Death spinning way more than it should! I'm tired of constantly having to wait for it to stop so I can continue.
Ironically, I installed two more Gigs of RAM less than six months ago so that I would have a faster computer, but I never really noticed a difference. Although it wasn't this slow the first few months.
Thanks in advance to anyone who can answer my two questions up above, and thanks for listening to me while I expressed my frustration.
Deb

Answer 1

Hi Deb,
This may be ten days late, and way, way too long, but you might want to try some of these suggestions, especially if AppleCare, or someone else, hasn't fixed it for you. You'll probably need to print out all this stuff. It's all stuff I've found useful in similar situations. There is no particular order to check things, but you might want check the utility "Activity Monitor" first and then try setting up a new account. That has worked for me.
Launch "Activity Monitor" (found in the utility folder inside the root Applications folder) and click on the CPU column to see if some background process or another application is running and using a large percentage of the processor's time. Also check the RAM columns to see if something is using a lot of the available RAM. If there is something that doesn't seem right, you can select it and double click the questionable item - a dialog box will appear that allows you to quit. That may solve the problem of spinning "pizza wheels" of death without a restart. At the least you'll have a good question to ask AppleCare (though they'll definitely suggest Activity Monitor.
You may also want to set up a new account in Apple Menu/System Prefs/Accounts with a different name and password. Then within that account try launching some apps from the Root Applications folder. They may now work in the new account. You can also install some apps you use most within the new account. Those apps will be placed in the Applications folder within the new home folder of the new account - NOT in the root Applications folder (the one you see when you double click the hard drive icon).
If you haven't set up a new account before it will seem strange when you first startup. Nothing is the same - the desktop, dock, etc will be like when the machine was new. But often, using the new account, and finding the sluggishness is now gone, tells you the problem was in the old account - even if you can't find what the problem was. The old account is still there. But setting up the new account will take some additional drive space if you reinstall applications.
Whatever you do, *_don't just delete the old account_* as that will also delete all your documents, videos, photos, etc. You can copy or move between accounts with your administrator password. The Library folder in the old Home folder will contain a lot of stuff you may want to keep, but also can contain the corrupt file that caused the sluggishness problem. You may want to copy the contents of different User/New Acct Home folder/Library folders a little at a time and reboot after changes. If the sluggishness reappears, then pull out the last items you put in and try to narrow it down.
If you don't want to set up a new account initially try some of these suggestions. Uninstall and reinstall the major applications that run slowly. Use the uninstaller that comes with the app. If there is none, then just reinstall and restart. That might solve the problem. Reinstall whatever apps you need. Can't hurt and may eliminate some file corruption.
After you restart, and BEFORE you launch any application, press and hold the Cmd (Apple) Key and then hit tab. You will see which apps are running in addition to the Finder. If there is stuff you didn't launch, keep pressing Cmd-Tab which will highlight each application. When selected, you can quit the application [Cmd-Q ]. Or just release the Cmd-Tab keys with the app selected and it's name should appear at the top left of the menu bar. There, you can pull down the menu and quit it (or press Cmd-Q). If it doesn't quit try to Force Quit [Opt-Cmd-Escape]. Try not to quit the Finder. Then launch the apps you need and see if they are still sluggish.
If there was stuff running and you don't know why, check your Account (Apple Menu/System Prefs/Accounts). Accounts is the first item on the System row (next to last row down). Click Accounts and when it opens, click the the account you're using (if there are more than one). Then click the Login Items tab near the top of the window. You'll see a list of apps that launch whenever you start up (sometimes in the background). If you don't recognize some of what's there you can remove them using the [-] icon. You'll have to unlock the account with your password and then re-lock it to prevent others from changing stuff.
Restart or log-out and log-in and see if the machine is faster without one or more of the removed items. There are things that are best not touched, but you'll probably know by their names. Pretty much anything you'd add will be found in the Applications or Utility folders. Other stuff is added by applications when they are installed. Make a list of whatever you remove if you have to add it back. If an application needs something you removed, you may be asked to reinstall the app.
That's it - hope it helps.
MartyP