If you still have the items that came with your computer, it will come with a disc that can help you restore to factory settings.

Every computer usually has a function key that allows you to enter restore/recovery mode upon startup, so use a google search of your computer model to find out what function key that is.

If you don't have a disc, your only option from there is to buy one online or just go through and delete things, but i'm not exactly sure what you're asking here.

If there's something you think is hiding your files, run task manager or regedit and look through the processes/partitions and see if you notice anything suspicious. Always do a
google search on it before deleting, though.

Try checking your firewall. Enable/disable, or add a custom program for the firewall to allow.

Also, try and check for corrupt files by using windows repair.
Run cmd as admin> type sfc /scannow> hit enter
Wait for it to finish scanning.

Good luck.