My cleaner favourites are:
SKTools features
MemMaid - DinarSoft
Try the demos so see if they are any help. The fact that you have to always do a soft reset implies a memory problem, as you also said. Remember that clicking on the X at the top right corner doesn't close the app unless you have installed a utility to do so.
Unless you absolutely cannot afford to lose your installed programs or data, I'd try a hard reset to start fresh. Then reinstall only those apps you need and to memory card or built in storage as much as possible. Some apps may require main memory installation, but keep those to a minimum. Also, install a proper application manager (one that closes programs) and cleaner.