Yes, I'd shut it off now, and use something else , it sounds like a lot of junk has gotten on to it somehow..
No way to know if it is secretly sending files to some other computer somewhere..It could be or maybe not..

Or if you don't have anything too special on the computer you can format the hard drive and reinstall a fresh operating system if you have the CD to do it....

But there is some malware of some sort making the pop ups and weird things happen...