Is there a site like pc pitstop?

I used to use this site to figure out why my pc was running slow. I haven't used it in years and needed to scan my pc, so I went there. I can't seem to scan (the "let's go" button is missing) despite trying 3 different browsers, including one in safe mode. I tried going to the forums to ask advice but after registering it says I am not allowed to visit the forums at all. WTF. So now even if I log out, I can't see what others have posted about how to make it work (before I registered I could read posts, just couldn't post my own questions). Anyway I'm over it and want to find a different site. Anyone know of one?