Hi, I'm gonna upgrade my PC from P3 733MHz to AMD64 3GHz or P4 3GHz. Is it gonna be okay if I just change the CPU and motherboard without re-install the Windows? Or do I need to change the settings to make it compatible? The current system often crashes when only few applications are running. Is the problem mainly lies on the CPU or the RAM? I used spyware & Ad-aware cleaner, and the running processes and auto start-up applications are monitored and controlled. Any help or comments would be much appreciated. Thanks a lot!!! =)

Hopefully you realize this will not just be a simple board/CPU swap. You will need a new power supply, new RAM, & possibly a new video card. Asus A7N8X-X 1800+ @8x210mhz 512mb PC3200 Ti4200/8X 128mb WDC 60GB

You should run Memtest86 for a couple of hours to see if it's a ram problem. Especially if the crashes happen in different situations it's very likely that it's a ram problem. About the upgrade I agree with jam. I'm just going to do the same but I had an older socketA system! A 300W PSU may work or may not. That depends very much on the build of it and the real power output. But in everycase the PSU needs the additional 4 wire power connector. You still have SD Ram but depending on the board you will need DDR Ram or DDR2 Ram. If you still use an old harddrive (ATA33) you should think about a new one because that will slow you down. For the new mainboard I suggest socket939. They are available with AGP (you can still use your graphic card) or the new ones with PCI Express!

What about the software? Can I still use my old system? Or I need to format the whole hard disk? =(

you can just do a repair install, but if you don't want problems, the best way is to format and start fresh MSI k7n2 delta L Thred A 1800+ @ 1833 MHz11.0 * 166mhz 512 pc2700 ATI AIW 7500 xp pro

On the repair install go to your device manager nad uninstall all of the devices in there first hit cancel for each one that ask you "do you want to restart your pc" After you uninstalled all of the old drivers in there etc.. shut down your pc. after you are done building the new one and installed the hard drive turn on your pc and hit F8 and do a repair install. You really won't run into problems if you do that. The only times i would suggest to redo everything is if your Windows has been hit with a few bad viruses in the past or if your Windows has been running without a reformat for longer then a year and a half. Windows degrades itself over time anyhow to get the best out of it many computer programmers agree that a refort windows every year to year and a half is the way to go.