Defrag your Windows PC For Free with Defraggler
Piriform's Defraggler program is a decent piece of freeware that does a good job and is very fast. It also allows you to schedule your defrag jobs.
7-Zip The Only File Compression Program You Will Need
If you deal with compressed files all the time you want a fast and free compression tool, 7-Zip is the program that I use solely for the past several months.