Mouse cursor lagging during hard disk access

My sister has an old P4 1.7GHz with 1GB of memory that she uses for her kids
and it has a terrible problem with mouse cursor lag while the hard drives
are being accessed. I didn't devote any time to troubleshooting it as
neither she nor the kids seemed to mind it, but I'd never seen it before.

However I just put together a newer PC for them to use, and it's having the
same problem. This is the setup of this box:

- Intel Celeron D 326 (2.53GHz, 533 MHz FSB)
- 1GB (2x512) Corsair Value Select DDR2 533 (PC4200) RAM in dual-channel
mode.
- GIGABYTE GA-8I945GZME-RH LGA 775 Intel 945GZ Micro ATX Intel Motherboard
- eVGA GeForce 6800 GT Ultra PCI-E video card 256MB DDR2
- Western Digital 20GB IDE HDD
- Using onboard audio/LAN from motherboard
- Fresh install of Windows XP Professional SP2. No other applications are
installed besides all critical updates.

When the hard disk is being accessed quite a bit (such as during an Office
installation) the mouse cursor lags to beat the band. I've tried using both
PS/2 and USB mouse/keyboard but it doesn't seem to make any difference.

What sort of things could be causing this? The machine they're using right
now has a Western Digital 250GB in it, but I don't know what the system
drive is. Thanks in advance for any thoughts.

Joe

My sister has an old P4 1.7GHz with 1GB of memory that she uses for her kids
and it has a terrible problem with mouse cursor lag while the hard drives
are being accessed. I didn't devote any time to troubleshooting it as
neither she nor the kids seemed to mind it, but I'd never seen it before.

However I just put together a newer PC for them to use, and it's having the
same problem. This is the setup of this box:

- Intel Celeron D 326 (2.53GHz, 533 MHz FSB)
- 1GB (2x512) Corsair Value Select DDR2 533 (PC4200) RAM in dual-channel
mode.
- GIGABYTE GA-8I945GZME-RH LGA 775 Intel 945GZ Micro ATX Intel Motherboard
- eVGA GeForce 6800 GT Ultra PCI-E video card 256MB DDR2
- Western Digital 20GB IDE HDD
- Using onboard audio/LAN from motherboard
- Fresh install of Windows XP Professional SP2. No other applications are
installed besides all critical updates.

When the hard disk is being accessed quite a bit (such as during an Office
installation) the mouse cursor lags to beat the band. I've tried using both
PS/2 and USB mouse/keyboard but it doesn't seem to make any difference.

What sort of things could be causing this? The machine they're using right
now has a Western Digital 250GB in it, but I don't know what the system
drive is. Thanks in advance for any thoughts.

Joe