Hi all, So I recently went through a rebuild of my 9-year old system (long story, read here: New Video Card = MB won't post? ). This included a new HDD, new video card, new power supply, and more RAM. I got each piece one at a time (the initial effort was just to replace the video card). Because the motherboard is 9 years old, the video card is old to compensate (got it on ebay) but the rest is relatively new stuff. The reason why I ended up buying a whole bunch of extra stuff is because I noticed that when I got the system running, there would be this wierd lag that occurred when I moved a window around on the desktop. The window wouldn't drag smoothly; i.e., there would be white artifacts left on the desktop where the window was for a half second or so before the desktop redrew the background. When I checked task manager, it became clear that the lag was because the cpu was spiking to 100% on explorer.exe. At first I thought that this might be due to some sort of virus or malware resident in the data I backed up and restored, however after doing 5-10 tries at reinstalling XP, eventually I found that I had this same behavior on a fresh install of XP that had not loaded any extra software and had only connected to the internet to go through the Windows Update process. Thus, unless somehow my router or microsoft has been compromised, there can't be anything shady going on causing the problem. What really got me confused was the fact that I didn't have this behavior before I started the reinstall process. That caused me to do the Windows Update process one step at a time until it started happening. What I found was, for whatever reason, updating to IE8 causes this problem on my computer. And more interestingly, reverting to IE7 clears it up! Another piece of information I more recently discovered is that one thing I can do to resolve at least the window-dragging symptom is to right click my computer > advanced > (performance) settings > unclick "show window contents while dragging". This provides some improvement on my computer, but I'm sure it's just hiding the real problem, not solving it, especially since I can drag windows around on my work computer (running XP) without any noticeable spike in cpu usage of explorer.exe. So what do I think it is? Well, I've tried swapping pretty much everything hardware-wise except the motherboard and cpu (which I'm going to not do, because I plan on building a new machine soon enough, this is just my internet computer). I've made sure that the problem crops up in a clean xp install with absolutely no additional files or programs introduced, and I've identified installing IE8 as something that triggers the problem (probably because IE8 provides a new explorer.exe, at least that was my understanding). So my best guess is that there is some sort of hardware incompatibility with my older motherboard, cpu, or video card (it's a 2x/4x AGP, not one of the newer ones) that's causing the problem. Here are the specs associated with my computer: CPU: 1.4Ghz Athlon XP 1500+ RAM: 2 GB (1GB new) OS: XP Pro w/ SP3 fully updated Motherboard: MSI MS-6712 Power Supply (new): Corsair CMPSU-450VX Video Card (new-ish): ATI Radeon 9800 Pro HDD running windows (new): Western Digital Caviar Blue (7200 RPM, 320GB, EIDE) I did download the most recent drivers for my video card from ATI's site, they didn't seem to have much effect (if any) on performance. In addition, I did look at the RAM as a potential cause. I have the following for RAM: 1x Corsair CMR1G400 2x Corsair VS512MB333 Both types are DDR, not DDR2, so my understanding is that they should work for my motherboard. There are 3 slots for RAM in my motherboard. One of the first things I did was to try every possible combination of the RAM sticks in every different slot. That means I did the following: -Old stick of RAM, by itself, in each slot -Each new stick of RAM, by itself, in each slot -Each combination of 2 sticks of RAM in each slot configuration -All 3 sticks at once, in each slot configuration Every single configuration resulted in the same problem, so unless all 3 sticks are bad in exactly the same way, I'm pretty sure it's not the RAM. Any suggestions anyone can provide on what else I can look at, or if I just need to give up and build a new computer, would be much appreciated.2 people need an answerI do too