It's always helpful if you tell us which system model you have.  Try clearing NVRAM by using the instructions specific to your computer model at the following site:

Steve

Hi Steve

 

Thanks for that but it still will not let me back into the BIOS - I have a Dimension XPS B1000r.  I set the jumpers on the motherboard to maintenance mode but it flags starting setup but does not get any further - just comes up with multi-bit ecc error system halted.  While looking in the Dell documentation for this model I found the codes on the back of the PC ABCD lights and these were set to A abd B yellow, C and D green which according to the documentation meant that the memory had failed to be sized or enabled and suggested reseating the RIMMS which I did also but to no avail.  Any other ideas?

Sandra

Replace the CMOS battery - scrambled CMOS contents can produce this type of spurious error.

I'm having the same problem helping a friend with his Dimension XPS B533r. There hadn't been any new software installed recently when it began to crash in certain applications. (I don't know which apps they were.) Then, it began to hang on bootup with a Windows Protection Error. If you tried to go into Safe Mode, the machine would bluescreen. (I don't have the BSOD details either.) So I chose Step-by-Step Confirmation. After loading the msmouse virtual device driver would come the Windows Protection Error again. But then I couldn't even get that far. It progressed to hanging during the POST with a 'Multi-bit ECC ErrorSystem Halted' message and the same diagnostic light code on the back (A & B yellow, C & D green; Memory failed to be sized or enabled).
I've tried the suggested solutions from the Dell Knowledge Base and this thread. It won't go any further than the Multi-bit ECC Error now.
Is this a memory problem? Does the RIMM need replacing? Thanks for any help or suggestions you can provide.

Did you ever get a response to this message?  I am having almost the identical problem on a Dimension XPS B800r.  Currently I have the Multi-bit ECC Error system halted message on boot.  I can't even get to the bios to change anything.  Another problem I had just before this was that the computer would restart itself whenever it got to the Windows 98 screen.

 

If you have learned anything I would appreciate the knowledge.

Thanks

It's all pointing towards the RAM.

I eventually managed to get back into BIOS by removing the CMOS battery and leaving it for 30 mins or so (make sure you follow the Dell instructions re accessing the battery and making sure you do not create static etc.).  When I replaced the battery and rebooted the PC I managed to get back into CMOS - I was advised to changed the memory type to Non ECC and it worked.  It then did not fall over and give me the Multi-bit ECC Error system halted fault.  However BIOS is now only counting up to 56MB of the 256MB of RAM that is installed (which is probably why my initial problems started - although I have yet to figure out why that has happened) so I think the RIMMS in my case needs replacing but it did get me beyond the nightmare of not being able to find out what the problem was or to run any diagnostics.  Worth a try!  Hope it helps - if you know of any reasons why BIOS won't count all the memory other than dodgy memory would appreciate your thoughts!

I eventually managed to get back into BIOS by removing the CMOS battery and leaving it for 30 mins or so (make sure you follow the Dell instructions re accessing the battery and making sure you do not create static etc.).  When I replaced the battery and rebooted the PC I managed to get back into CMOS - I was advised to change the memory type to Non ECC and it worked.  It then did not fall over and give me the Multi-bit ECC Error system halted fault.  However BIOS is now only counting up to 56MB of the 256MB of RAM that is installed (which is probably why my initial problems started - although I have yet to figure out why that has happened) so I think the RIMMS in my case needs replacing but it did get me beyond the nightmare of not being able to find out what the problem was or to run any diagnostics.  Worth a try!  Hope it helps - if you know of any reasons why BIOS won't count all the memory other than dodgy memory would appreciate your thoughts!

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@doris2 wrote:
I eventually managed to get back into BIOS by removing the CMOS battery and leaving it for 30 mins or so (make sure you follow the Dell instructions re accessing the battery and making sure you do not create static etc.).  When I replaced the battery and rebooted the PC I managed to get back into CMOS - I was advised to change the memory type to Non ECC and it worked.  It then did not fall over and give me the Multi-bit ECC Error system halted fault.  However BIOS is now only counting up to 56MB of the 256MB of RAM that is installed (which is probably why my initial problems started - although I have yet to figure out why that has happened) so I think the RIMMS in my case needs replacing but it did get me beyond the nightmare of not being able to find out what the problem was or to run any diagnostics.  Worth a try!  Hope it helps - if you know of any reasons why BIOS won't count all the memory other than dodgy memory would appreciate your thoughts!

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This could also be caused by you mixing Non-ECC RDRAM and ECC-RDRAM by mistake.  Normally, it wouldn't boot at all, but in some rare cases you can get it too boot (I've done it - by mistake). 

Replacing the RAM module worked for me.