Reinstall *all* packages. How?

["ocl@arayan.com" <ocl@arayan.com>]

Hi,

I am able to login the amd64 box anymore, I have practically
lost it as a bootable one.

I do however have a lot of stuff (about 2GB) in

/var/cache/apt/archives/

My question is: After setting up a fresh system from CD,
how can I make the newly installed OS update itself from
these already downloaded packages.

I have tried a simple copy of the old /var/cache/apt/archives/
to the new installation, but simply copying the packages
does not seem to work.

Short of creating my local Debian repository, is there a
way I can instruct apt-get (or aptitude) to use the files
already downloaded.

What I really want to do is a complete reinstall of the
packages I have. Is that possible?

Cheers,
Ray