C:\Documents and Settings\Owner\Local Settings\Temp
 

Can I delete the contents of this huge folder?

Absolutely!

This directory is the place where Windows, other software, and setup programs store files temporarily.

Unfortunately, some programs are not very good about cleaning up after themselves and leave files and folders behind.
Everything there can and must be deleted on a regular basis, preferably after rebooting Windows, so as to be sure that no files will be in use.

Thankz

Is there an automatic process or do I have to do it?

It's best to do it yourself. There are folks who have the folder emptied on boot using a batch file, but I don't recommend that.

Some programs put stuff in your Windows\Temp folder during setup that they need on reboot to complete the install..

If on reboot they find the folder empty, they may not be able to.

So how will I know? I guess I can delete contents if...
I have not installed or changed any programs...

thankz

You'll know. It happens only when during setup the installer requests a reboot in order to complete the install.

If you're not in the middle of an install it's always OK to empty your temp folder.

If any file there is in use, you'll be notified, and you'll be able to skip that one.
Often the file can be deleted after a further reboot.