Only two registry cleaners I can recommend, RegscrubVistaXp and Ccleaner's. Both free and are basic but ample to keep the registry optimised.
Be very careful using Optimizer programs as they will eventually give way to problems. Have tried a lot of them in the past, including Ashampoo's winoptimizer and they've all ended in the bin.
Try a system restore to nearest highlighted date to when you reinstalled Windows. If no optimising programs there then leave it like that. Just make sure security applications up to date and Windows update is err up to date.