Registry for applications, temporary folder for files.

For applications, use
MRU BlasterFor files, it's slightly harder.
There's lot of folders to look at.
C:\Documents and Settings\username\Local Settings\Temp
C:\Documents and Settings\username\Local Settings\History
C:\Documents and Settings\username\Local Settings\Temporary Internet Files
C:\Documents and Settings\username\Recent
C:\WINDOWS\Temp