How to reset the bios on a acer 5100

Check windows device manager for conflicts. Control panel>system>hardware>device manager. If you have any devices with a mark next to them, try uninstalling the device and reboot, letting windows reinstall the device driver, or use the update driver option and let windows search for a newer one.

Sounds good. but the computer will not come on. So can I reset the cmos and jumping the bios chep

You can try. Don't know if your board has a small battery you can simply remove for one minute. That will reset the bios for sure, but still may not get your system going. Nothing will save a bad bios flash if the bios chip is soldered on, except for a few recovery programs, but I doubt acer has any.