HD Space vanished? Duplicated files maybe?

[Kamikaze]

Hello,
My 24" iMac (10.4.10) had around 20-25gb of free space left on it. I quit converting my DVD collection until I could get a mass storage/backup solution set up this weekend. Last night I had the above free space left out of the 232 available. My kids may have been clicking on things I'm not sure. When I got home today I had a message that my startup disc was full. I now have 2gb of free space left.😕
Is there any software/utility that i can use to help track down duplicate files or that can tell me what the last files were that were modified? If not I will copy my files that I need to the new storage and wipe the drive and reinstall everything then move my docs and media back to it. 😀
Thanks for any and all help with this.
One more thing my unit runs an average temp of 100F and It was at 144F when I got home and saw the error message.

 

[iPhil]

How many dvds you've converted since you got the machine ?


Each full content dvd done thru MTR (MacTheRipper) is usually 6-8 GB in file size.. got any other apps installed besides the 'basics'

 

[Samwise592]

There's a great free utility called "Disk Inventory X" its got a cool visual way of showing you where all your data is, and whats taking up the most space.

I use it to find large, lost files that need deleting.