Booted It Up, Everything Has Significantly Slowed Down?

At the beginning of the problem when I booted up my computer, I would check to see if the built-in wi-fi was working. If it wasn't, then it would freeze up at some point (usually soon after) and I was forced to restart. Whenever I booted my computer up and saw this problem, I restarted immediately. If the wi-fi was working, then the computer functioned normally. This was only an occasional problem, so I was able to deal with it by restarting when I found the problem.Then, a couple of weeks ago, my computer automatically forced a hard drive scan upon startup and found 4 corrupted segements on my disk. Next time it booted up, it scanned again and the errors had dissapeared.

Unfortunately, my problem worsened yesterday. When I booted it up, everything has significantly slowed down. It hangs on the Windows screen before I choose my profile, after I choose my profile, when it's loading my profile, and when I perform any task. I tried to start it in Safe Mode and found the same problem. I've found that if I just wait around (usually about 30 minutes), the computer catches up to itself and can perform normally for a while until I start to perform a demanding test. Then it hangs again. Can anyone identify a probable problem? It seems like it is a hardware problem mainly because it isn't an isolated event.