How do I stop my taskbar & file explorer from crashing?

Not so long ago I downloaded a program packed with a virus that installed many many programs on my computer. I was quick to resolve this, removing the programs, deleting any relevant files and making sure there was nothing damaging left. Since then, the only problem that's remained is that whenever I click an icon on the taskbar it crashes and restarts. Also, whenever I try to right click or use some other basic functions in file explorer it does the same thing. How do I stop this from happening? Thanks for any help guys.

It could be that File Explorer has context menu handlers in the Registry that do not exist, since they were deleted when you cleaned off the virus. One quick thing to try is the Registry Cleaner in CCleaner.