Why don't you have a go at doing it yourself? There's a plethora of free software to help you.
Spybot is handy for removing dead DLL's, leftover installation files, etc
Hijack this can be good if you've a probem with pop ups or similar
CC cleaner used to be alright - not used it for years though.
Just prepare prior to the cleaning. Backup you data, make a list of the programs you have and want to keep, note any registration keys you have.
People here will always help.