Cleaning up temp. files is no problem. Use this for starters. Disk Cleanup : Extended
Ccleaner is another little program that can do that. I recommend not using the registry part of Ccleaner. TFC bYy Old Timer is another good little program that works for such things. After your temps are clean reboot.
What would bother me the most is how did these files get put some where I didn't put them. I would run from the cmd. prompt/admin sfc /scannow. If System File Checker finds problems run it 3 times booting after each time.
What security do you have on your computer and have you run scans?
Please fill in your System Specs.