lol
ethel - I'm surprised at you!... I thought you were a chancer
these files (actually folders - compressed folder to be exact ... they are blue) are all the hotfixes, security updates .... and yes service packs that have been installed on your 'puter.
Or rather they are the files required to uninstall them if there is a problem.
the "rule" I use is update the PC .... see how things run - I generally give an update at least two weeks ... often a month.
once I'm reasonably sure that my system is stable ... I delete them.....
I never touch
ie7
and microsoft say you should NEVER EVER delete
$hf_mig$ .
(it's actually the manifest for all your updates - if you do delete it - update downloads and installs all of them again... so it's a pain ... but not a disaster
this is free
http://www.ccleaner.com/download
and it works well and is very safe ... use the default settings and it will recover tons of wasted space ...
if you bank and remember passwords ... take the tick out of cookies in the IE section before you run it
ccleaner will delete the safe stuff for you