Complex Computer Problem?

I have an HP computer that came with Windows 7 and has an Intel i5 core inside. Recently, it has refused to connect to the internet.... Actually, it is directly connected to our wifi router, and it says that we should have internet access, but when I try to go on Internet Explorer, I get an error message that says that I failed to connect to the internet. My computer also refuses to connect to the printer and my iPad. I do have Minecraft on my computer, which caused some overheating issues in the past, so I got a fan pad so that it would remain cool when I was using it. However, the computer now heats up and sounds like a plane taking off when I turn it on and log on my account. I tried to download optifine (or something along those lines) so that my computer would stop overheating when I played Minecraft, but my computer rejected it, thinking that it was a virus.

I also have Stopzilla installed to prevent malware from popping up, and it has been warning me about lots of cookies that are potentially dangerous. At the last count, there were over 200 of them that I had Stopzilla take care of. I disabled all cookies in my internet settings, so hopefully this will no longer be a problem.

I have also sent my computer in for servicing once. The hard drive was damaged, and the company that made my computer wiped everything and reset it to factory settings before transferring the account info to a new computer and sending it back.

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So is there anything that I can do to fix my computer before I send it in for servicing again? Or should I look into getting a new computer and save myself the trouble?