If you "Open from location" instead of "Save to Disk", does this mean the file is not really saved on your computer?

C;/Users/[username]/apps/roaming/temp

It is saved, but it’s saved to a temp file which may (or may not) get deleted within a short period of time.
If you use Firefox, it will go into C:\Documents and Settings\[YOUR USERNAME HERE]\Local Settings\Temp

oops, reverse those slashes. how sloppy of me.

I’m saving this question for future use.

It might be noteworthy that the files in this folder are deleted upon (reboot?)

There’s some control somewhere to set how regularly things get purged (May vary from browser to browser, and OS to OS). I’ve got things in my /Temp/ folder last modified in July, which is around the time that I had gone through and deleted a lot of crap.

thanks you all

Well if its something you wish to keep, its best to make a couple of choices here:
1. view it first, if its something of value
2. choose to now save it, as to where its your choice
3 choose save as: you will get a drop down list of: my documents to CD, DVD, jumpdrive etc
pick one and put it there or in more than one of them if its real important.