Can't remove old files

I bought an Upgrade Version of Windows Vista, both 32 and 64bit. I went about upgrading the old version of vista home that I had, and a window came up and said it cant upgrade this version, and to boot from the CD. I done that and it said to install in any location, I wanted to install in the same location as Vista Home and pointed it to there. As it started the process it said the was an operating system on the drive and it would intall the my new version and backup the old version as Old Windows. I went ahead thinking there would be no problems about that as I could delete it when I had the new Vista Premium up and running. But it will not allow me to, as it says I do not have permission. I am set up as administrator, and have tried to take possion of the files, but I cn't get round it. I must be doing something wrong, I would not know a lot about taking posession of files or setting up security permission. Any help would be greatle appreciated, as it is taking up 11**Gb of my drive.

Thanks..........Irish Bear

 

Thanks for the reply Halo, had already tried the safe mode method, but just tried the disk cleanup, and no mention at all of old Windows Files.:cry

 

In many of the tweaks around and about VistaBase, you sometimes need to delete or replace a system file. In Windows Vista this is not always as easy as it sounds since the system files are protected better by the file system than in XP. There are two steps that you need to do in order to be able to replace or delete a system file:

1. First you need to take ownership of the file. At the Run command (press Windows key + R), type in:
takeown /f “path and file name” to take ownership from a command prompt.
2. Next, you need to give your account full control permissions on the file. Run from the same command prompt:
cacls “path and file name” /G <your username>:F to get full control from a command prompt.

 

Done that and was able to delete some of the files. And when I tried what Halo said it did not find the Windows.old because somehow the folder got renamed xxxxxxx.xxx and the same with some of the subfolders, one of them had about 20X's, then I remembered that I had backed up my installation as soon as I had all drivers and most of the major progs that I use installed. I done a restore and there it was "windows.old" Now I done what halo said and it was gone in a few minuets.
Thanks for all the help everyone