i've used 8.1 for forever and i recommend a registry clean, if not then a windows reset but saving files, last but not least a factory reset after backing up your stuff.

i read this dick usage 100% and thats why i clicked on the thread

how much memory do you have? you might be using the disk swap file and thrashing your io

try this and see the health status of your hard drive
crystal disk info
you might have a bad drive

qsd