Can I limit computer access in win 8.1 for a specific user to specified programs. Can I make all my hard drives & networking off limits to said user?

Hi Proost L,

If it is possible ,please share us the exact applying environment of this issue .

According to your description ,the Family Safety feature maybe useful .
Set up Family Safety
http://windows.microsoft.com/en-HK/windows/set-up-family-safety#set-up-family-safety=windows-8

Apart from this ,we can change the security properties of specific drives ,programs for the specific user to restrict the access .

Best regards