1) Irishlad74 should type in *.tmp (note the extra "*") to find any files which are temporary files. Also try *.txt, *.htm & *.jpg (Note - not all of these will be temporary files, some may be needed by programs already installed.) So...when you use the "Start>Search" option, go down to the window which says "look in".
Click on the button which says "browse", then click on the "Local Disk C:" drive in the next window. and in that window you'll then see a file called "Windows". Click on this folder and you'll then see another file called "temp".
Now click "search" and it should find the files you're looking for.
2) By far the easiest way to get rid of temporary files is to go to
www.ccleaner.com and download a program called "Ccleaner slim". Install it, and when it has installed, run it, and press the button which says "run cleaner". Once it has done this, all the temporary files will have gone.