I can not access my computer because it comes up

as your machine is booting, press F2 or Del key repeatedly, which will get you into system BIOS. Then go through the BIOS settings page by page until you see something glaringly wrong or highlighted.
You should also be able to disable system halts for such things as keyboard and mouse errors, with an 'all errors' setting as well, but use that one with caution, in case it's not something simple.
Note: If you continually get 'checksum error', or if your date and time keep resetting every time you reboot the system, your motherboard battery is shot and needs to be replaced.