Hi, I have two DIMMs of 512 MB DDR each. i purchased the second one some days ago. I installed the new RAM and it worked fine. Had no problems at that time. I also purchased new SATA Seagate HDD of 160 GB about 3 months ago. But it has got bad sectors so i had removed it, and, i have been working with my 8 GB old Seagate HDD. The HDD is another issue for which i will post another topic. So 2 days ago, i had to take some data out of my bad HDD. So i cleaned my PC of some dust(I do that in few days), and then plugged in, the bad SATA HDD. When i powered up, it gave the same error as it is giving now i.e. when i power up the PC, it says: Maximum memory performance is achieved with matched DIMMs. The installed amount of memory in channel A is not equal to the amount of(message was truncated, couldnt see what was written ahead). Press any key to continue.. When i pressed a key, then it says: CMOS/GPNV checksum bad CMOS Date/Time not set Then i have to get into BIOS, set the date and time and also the boot order, and save the changes. And then the PC boots up fine. But everytime i shutdown and start the PC, again it starts showing the same message. I have reseated the DIMMs too. Why is this happening? About 8 MB i think goes for the video memory, so it shows 1016 MB of RAM on startup. Uptill now the PC was working fine. Why the error now? I have also removed the bad HDD. Looking forward to answers. Thanks Anupam

The CMOS battery is apparently too weak to retain the BIOS settings in memory when the PC is powered off. Change the battery.

I would guess the battery on the motherboard has gone dead. That battery holds the BIOS settings whenever the computer is shutdown and removed from the AC power. If the computer is off but plugged in, the AC power will still keep those settings. You must have unplugged the competer, as you should have, to mess with the innards. The battery is flat silver and coin shaped. You should be able to find a replacement at any computer shop of at Radio Shack. You will need to reset many settings after replacing the battery. In the meantime Boot into the BIOS screens (setup) by tapping delete at startup. Reset the time and date and any other settings that may be wrong. Consult your MBoard manual for more help with those settings. Now, as far as your 160GB hard drive goes I would suspect your computer BIOS is not 48bit LBA compliant. What that means is it can't properly access a hard drive larger than about 127GB. Using a drive larger than that will result in data corruption. You could install a hard drive controller card that would allow the proper use of that 160GB drive. Look at the link below for further info on 48 bit LBA compliance. 48bitLBA.com

Sorry for late reply... was having problem with the internet. Well, the problem is solved. I reseated the RAMs, and since then, the PC is booting fine. No CMOS message occurred again. About the HDD, well.. my PC is a fairly new one.. and i think the BIOS recognises the full capacity of the drive. I myself formatted and installed OS on the drive, and it showed the full capacity. So, i dont think the capacity being recognised by BIOS is of any issue. Anyways, my HDD is a SATA one, and 48-bit problem is said for IDE devices. So does it apply to a SATA HD , or only to ATA drives? Thanks again for the replies. Anupam