My Dimension 2400 with Windows XP keeps losing then finding again user information and when I try to join to a domain comes up with a message that the stub has bad data. Similar messages come up when I try to set up a user and the system loses user type (e.g. user set up as administrator becomes a different type and can not be reset to administrator). If I am using XP Home and have the welcome screen startup sometimes there are no users at all to click on and I have to reboot several times to have uses displayed.

I also have trouble with MSI for installing programs. I have done all the MS fixes and it will work for one installation then fails again.

I have loaded XP Home, XP with SP1a and XP with SP2 but get the same problems. Each time I fully formatted the hard drive (complete drive, left no partitions). I have changed the hard drive but to no avail. I have run the full Dell diagnostics but no errors can be found in any of the hardware. I have gone over the system with AVG but no virus has been found.

It seems to be a hardware memory or processor fault but very strange as it is consistently in the same area(s). I am at a loss to come up with an answer and hope someone has the magic fix as I have spent considerable hours trying to resolve this.

Please...