I have PC ACER VERITON X2640 version BIOS R02-B1 How do I downgrade to version R01-B1???

Acer does NOT recommend their bios versions to be rolled back, Acer community EULA does not allow members to give any guides on anything bios related that might brick your Acer product. I suggest that you leave the Veriton X2640 desktops latest bios version R02-B1 like it is and you DO NOT roll it back to a previous version. Good luck.

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Its not the bios, do you get BSOD and if you do what is the error code, as it could be faulty hardware that your desktop has. Its very rare that a bios will make your computer restart. Give us more details, if you can't get into the bios and system do a hard reset of the X2640 desktop.

To do a Hard Reset do this: take the RTC/BIOS battery out (see caption below) and short the mainboard RTC/BIOS battery pugs +&- pins to reset CMOS, then take the ram (one or two ram modules out) and leave the desktop like that for 15min until the EC chip and chipset chip reset properly.

Then reconnect everything back but if you have more than one ram module, only connect one ram module back, and see if the ram is not faulty. Do that and let us know if your desktop boots properly, otherwise you have other problems like overheating, viruses, outdated software, and failing hardware. Good luck

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