Hello, Recently (about 4 days ago), I reformatted my hard drive and installed Windows XP, but ever since the CPU usage has been acting up, and whenever it goes over 50 percent the mouse starts to lag every 2 seconds (exactly 2 seconds between each lag spike), and its not one program - its all of them, for example, I launch Firefox, it can take like 50-65 cpu, and Kaspersky and spyware doctor (these are just examples). So whenever a handful of software is running the cpu is always 100 and the computer is really slow, I mean you have to wait minutes, because it won't go off the 100 percent. This never happened before until recently like 2 days after I reformatted, I searched for answers on this on the net but to no avail. So I started tinkering, at first I only thought it was my mouse that had the problem but I discovered that it was the whole system, every 2 seconds it freezes (for like 1/4 of a second), for example in games, and in movies. I've read about USB mouses which I have and it occurred to me that maybe it was a problem with the transmit rate with the mouse, so I got the USBtoPS/2 connector out of the drawer and I put it there, and then I changed the transition to the highest one (i think it was like 200), but still the same problem. This is my system: Intel Pentium 4 x86 - 3.00GHZ Via motherboard model P4M800 ATI Radeon 9250 256mb AC'97 Audio 512MB of ram And on another subject - I've read about Hyper Threading technology and I can enable it in my BIOS, but some say it slowed down their software even more, is it worth it? Thanks in advance for the help Op.