Presario 1277 POST beeping

Hi all,

I have a compaq presario 1277. After a windows 98se to XP upgrade, the
keyboard started to behave erratically.It just didn't work or it didn't
output the correct characters.System worked fine otherwise.After a day
or so, the laptop started to emit beeps during the POST.one beep then 3
consecutive ones and again 1 beep and 3 beeps. The system won't go into
the bios setup and sometimes the following error would appear : ERROR
0280: Previous boot incomplete. Default configuration used. two options
are offered F1: continue boot F10: access bios setup. neither of the
two buttons work.
Are the 2 problems (keyboard not functioning and beeps) related do you
think?could xp have caused this problem?i tried to insert the xp
install. disc at boot up.it starts fine but then when it asks to press
Enter or R or ESC, i'm stuck since the keyboard won't respond.i tried
the same with compaq quickrestore CD.
what would you suggest?flash bios?replace the cmos battery?
thanks a lot for your help.
Simone