well i downloaded and tried the ccleaner...that works very well. however i do not feel using a different defrag program will work well, and i say this because in the past i have installed other defrag programs, and sometimes my pc would lock up.
for a time, i would use Norton's defrag, and that messed things up. i bought a reasonably good program before that, when used, it would mess things ups. then i tried a free program. in the end, Windows just didn't like those programs, and would lock up everything. something went horribly wrong one time, and i had to re-install Windows all over again. so for the past few years now, i use the Windows defrag. it works, it's compatible, no problems.
if you use any other defrag program and it works for you, you have my blessing.
on a side note, i do a disk clean once each week, clean out my restore points and make a new one, then i defrag...just "weekly maintenance" since i got this machine, back in 1999...!!!!