Temp files do not slow down your computer. However, they do clog up the file table that stores all of your other files and take up space on your drive.
Simple tips to speed up your computer:
Windows 10 or 8.1:
1. Right click start button, click task manager. Click the startup tab. Click and disable extra programs that you don't need, or even things you do use but do not need immediately on startup. If your computer is loading unnecessary programs when Windows boots, then it will slow things down until everything is loaded. The extra programs also use CPU processes that will slow your computer down the entire time you are using it. I bet you there are at least 5-10 things in there you can turn off.
2. Hit windows button, type (without quotes) "clean" and click on disk cleanup. Let that run to remove junk/temp files. This won't speed anything up, but it can remove thousands of files in preparation for the next step.
3. Hit windows button, type "defrag" and click on defragment and optimize drives. Let that run to piece together file fragments. If you on an SSD, this will issue a trim command which will make your drive more efficient for future writes. If you are on a mechanical hard disk drive, this will be a noticeable improvement to go along with numbers 1 and 2. Some files can have literally thousands of fragments / pieces. To load one of those files, your mechanical drive has to seek out each of the thousands of parts and stitch them together every time that file is accessed. This should be run often in my personal opinion.
Reboot after doing 1 - 3 and your computer will be about as fast as it can be. There is one more thing you could possibly do. If that still doesn't help, try making a new user account. User accounts get clogged up with crap too that even CCleaner or Windows built in junk cleaner won't get rid of. Making a new account is one way of starting fresh without totally wiping the computer.
Legacy Ancient Windows 7:
1. Check this link:
https://www.microsoft.com/en-us/software-download/windows10 Do a CLEAN install and not the stupid upgrade. Even if you didn't reserve your copy of W10, you can still download and use it for free without a valid CD key (just have a watermark in the lower right corner every other boot).
Windows 7 lost mainstream support in January 2015. Seriously, just update your computer or you will have nothing but problems in the future.