I wanted to try to upgrade to XP on this computer today. Before I put in the XP CD, I had 3+ gigs of free space on my C drive. I popped in the CD, it started preparing for the XP install and then it stopped and said I didn't have enough free space. After I cancelled the upgrade, I checked my HD again and it had less than 650 megs free when just moments before it had 3+ gigs. What happened??? I want my free space back!

Probably all the temp files from the CD were copied to your HD and weren't deleted when the install failed.

The question, now, is this: where does Windows copy the necessary install files for an XP install???

I was thinking the same thing, that the setup files were not removed from the hard drive when the setup failed.

I think the setup files are copied to a folder named I386 - the same named folder on the XP installation CD - but I'm not 100% sure of this. Never really thought about it.

I found 2 I386 folders on the computer.

One that's 104 KB in C:\Windows\Driver Cache
One that's 671 bytes in D:\Program Files\Java\J2re1.4.2\lib

(Oh, and D isn't a CD drive, my drives are: A = floppy; C = hard drive 1; D = hard drive 2; E, F, & G = USB card reader; H = CD-ROM; I = CD burner)

Any other ideas where these setup files could be hiding?

Maybe look for any setup or temp folders. The files may have been placed in the root of C: also.