Sorry, what you did was software piracy, and it's against the rules of these forums to help people who pirate software.
Feel free to come back when you get a legitimate (paid for) version of Windows.
I formatted my C drive to get rid of an annoying virus and other malware, and installed Windows XP Pro SP2 from a copy I found on the internet, because I lost my Windows XP CD.
Everything went ok, but now when there's a program running, especially if it takes up some processing power, Windows would stutter badly. It's very evident in the pointer. If I'm moving it, it would stutter for a fraction of time every 2 seconds. Before formatting, this stuttering (in this regular form) wouldn't happen. Generally, the PC now is fast. It's only that stuttering every now and then, but videos lag badly as well. I can see this stuttering generally happens when there's a lot of CPU usage.
I wonder if this has anything to do with the Windows I installed? Is it a bad version or missing something? I can download Windows updates, so it should be genuine.
Is there anything I can do to know if the version I installed is bad?