The Master Boot Record is on the first track of the HD.
It is not inside a partition.
It consists of two parts. A small piece of code called the Initial Program Loader (IPL) and the Partition Table.
When Bios finishes POST, it hands contol to the IPL, which consults the Partition Table to locate the partition marked Active.
Your problem appears to be connected with the Bios not recognising the keyboard correctly.
Did this only happen after installing Ubuntu - and where did you elect for the Ubuntu boot manager to be installed ?