Vista Install Issues

Hi. I am currently installing Vista 32bit on my rig. It’s not going very well but its happening. My question is I want to delete the windows.old files it’s putting on there. So far I have four of these .old files and windows.old100 files. Is this a good idea? Will it cause any damage if I do so? I just want a little as possible on my computer.
Thanks

Those may be "restore files" in case you want to turn back to XP.

I believe you can safely remove those files with the Vista disk cleanup utility.
http://windowshelp.microsoft.com/Windows/en-us/help/1264bc24-72a8-48aa-84e3-a355327139d91033.mspx

It will probably tell you don't have permission if you try to delete them manually.

If you delete them, you won't be able to access the information from any previous installs of windows.

You can browse through them and selectively delete what you don't need, or delete the whole folder if you choose.