Basically, whenever I boot up XP, the explorer will not start. If I try to run it from the Task Manager, it closes again in a matter of seconds. It will then try to open itself up again... but then closes. (Every time it reloads, it un-focuses any window, making this difficult to type x_x )

It started happening last night. I'll give a summary of what I did recently on the computer. Originally, I was facing problems with Norton Antivirus, where the list of unresolved security risks would not load. I contacted Tech Support, and they told me to reinstall it, which seemed to work. Meanwhile, I was also having trouble loading certain websites (EBay, Amazon, etc). I did some googling, and found a program called TCP Optimizer. I downloaded, installed, and ran that program, and "optimized" my router settings. After that was done, TCP Optimizer asked me to restart my Computer, which I did. After the computer rebooted, the explorer problems began (However, I can view those sites now x_x).

I did look around some other threads here concerning similar problems to the one I am currently facing, but they all seemed to reach dead ends, or were specific to the original poster. One thing I came across the most on these threads was a program called HijackThis, or something to that effect. I'm not really sure what it is, but I assume I'll be needing it to fix this problem. I'm not sure where to download it, though.