My system drive is 63GB - yes GB... All that's on there is Windows 7 64-bit, and my applications. Data is elsewhere, cache files are elsewhere..... At this moment there's 420KB free on the drive... So, I started looking for what honking big bunch of garbage is eating this thing. Searching just for files larger than 10MB. There's most likely some other stuff going on, but the first thing I found was a LOT of files in a couple places... Can I delete any of these without causing problems? c:\Windows\Installer\ has A LOT of files. With useful names like 68b8p.msp, which is 335MB by itself. There are 300 files in here, and it's taking better than 5GB... Anything in here I can delete? How about what's in the $PatchCache$ directory tree?