The Windows Disk Cleanup takes an unusually long amount of time to start. I have tried this on several computers including my own only to come up with the same results. Normally when I do Disk Cleanup, it would take so long that I would just cancel the operation. Last night, my brother wanted to see what would happen if we let it finish. After at least 10 minutes of waiting, it finally showed what we could clean up. 621MB of files could have been compressed! That's a hefty chunk. After compressing and defragmenting, we tried it again to see if it would still take that long to complete... and it did. I would like to know:

1.) Why does it take so long?
2.) Is there any way to speed it up?

Thanks in advance!