I just upgraded to an athlon 2600+ and have had many crashing issues. I upgraded my bios and it fixed most of the system halts. But my system seems sluggish. Just running a file sharing program with cause the system to run a 100% CPU constantly. Before the upgrade the same program only took 20-30% tops at peak. System Stats: MSI KT4A Ultra http://www.msi.com.tw/program/products/mainboard/mbd/pro_mbd_detail.php?UID=442 Athlon 2600+ (2.13ghz 266 FSB) 2 X 256 pc2100 ram = 512megs Geforce FX 5900 nic card Hercules Game Theater XP MSI TV@nywhere tuner card 600 watt PS Please help I'm getting desperate!

Sounds like you have one of the many variations of the sasser virus. Go to the following site and perform a full system scan allowing it to fix all errors and it should solve your problem. http://housecall.trendmicro.com/housecall/ Let me know if it works....

I had enough of trying to get this CPU working. I put my old athlon 1400 back in. What a performance boost. Rebooted in about 1/2 the time and when rebooted my usb devices were recognized and the system is stable. I tried manually setting the FSB and multiplier but the bios only had 15X as it's highest option. I tried that and the system wouldn't video post and even after clearing the cmos it wouldn't boot. I am worried the CPU got damaged. I'm not going to even try to put it back in with out some clear advice on what might have happened. I did notice a ram check that did not occur before after rebooting with the old proccessor back in.The MSI web site clearly says it supports this processor (link below).

Virus scan Complete and I am squeaky clean. Nothing found no sasser for sure.

This ain't BeOS. You can't just swap hardware. I suggest that you try a clean install with the new hardware and then use... Use event viewer, task manager or performance monitor to try to locate your problems. There are also ways to view dump log that you usually must direct xp to make if it can. See also Dr. Watson in help and support.

I did a clean install (and full format of c:) of XP after I noticed the first lock up. Didn't solve any problems. And as a side note I have installed different processors many times in 98 2000 and XP with 0 problems. Now installing a new Mobo is a different story but this was just a processor upgrade. I used event viewer and performance monitor nothing out of the ordinary just the processor running really slow while using the full proccessor load. And my system halts were memory faults that caused instant reboots. I couldn't even see the error location it rebooted so fast, let alone check a memory dump. I'm almost positive this was a bios/memory issue not software. Any clues?