You mention that it is an older computer. In your profile you have Microsoft Windows XP professional listed as the operating system.
Since you posted in the Windows 8 forum I have to ask which one are you using-XP or Windows 8?
My feeling is that since it is an older computer it's XP, but want to make sure. If it is XP your post can be moved to the XP forum.
When using system restore you don't save anything. All you need to do is choose the date/time you want to restore the system to and follow the prompts. If the restore is successful your computer will revert back to the way it was at that time. Hopefully Application Support will be restored.
Your other option is to NOT do a system restore. Instead, uninstall Quicktime and reinstall. You can also uninstall Apple Software Update.
A reinstall of Quicktime will also install Application Support and Software Update.
You might want to read this tutorial about System Restore http://www.bleepingcomputer.com/tutorials/windows-xp-system-restore-guide/
It explains what it is, what it does, and how to use it. Since you want to go back to a previous date, you will not have to create a restore point.
Follow the directions under Restoring Windows XP to a previous State (assuming you have XP. The process is the same for other versions of Windows)
It has been awhile since I've used XP so I hope this is correct. If you know when you removed the program look to see if that date is in bold and click on it.
If you decide to use System Restore here is something that could make it easier for you. Restore points will be on days that are in bold. If the date is in bold, choose the date. Next look to the right to see what is listed. You should see something to the effect that Apple Support was uninstalled. If you do, choose that as your restore point. Follow the prompts. Your computer will reboot and once again if successful the program should be restored. You can look in Add Remove programs-if restored it will be there.
If you don't know the exact date look at some of the bolded dates to see if it is listed.
It sounds complicated but it is not. After you use it for the first time it's one of those "wow, that was easy" things.
Edited by Queen-Evie, 18 May 2013 - 11:23 AM.