blank screen, 2 short beeps?

recently my pc has been playing up, sometimes it will crash and when i reboot the screen will just be blank and after a while it will make 2 short beeps, if i unplug from the mains and try again an hour or so later it seems ok but some of my settings will have changed (time, date, boot order etc, i thought the battery was dead inside because of this but changed it and still the same) it has been ok for the last week or so but im sure its only a matter of time before it starts playing up again , my computer is a compaq pc and i use windows vista, any help or suggestions would be greatly appreciated.

Did you receive some message from computer ? CMOS error or something like that.

Nazzgull wrote:

Did you receive some message from computer ? CMOS error or something like that.

nope just a blank screen

Okay, if you have two beeps it's RAM memory problem.
This is guide by Microsoft, you should try it first

http://oca.microsoft.com/en/windiag.asp

Put this on a floppy and boot to it.
If memory fails test, remove one at a time to find bad.