Boot problems

Hello,
I am having some similar problems.Initially I was not getting any connection from the cpu to the monitor quite a lot of times.Then it showd "bluee screen of death"symptoms,after startup,hanging badly and then the BSOD symptom.Now sometimes a black screen is shown after startup and everything hangs or boot screen hangs by itself or sometimes while booting my windows the screen hangs and stucks up there.Also during boot,the functional keys are not working.So i cannot check the hard disk.I have a dual boot system with suse and windows xp,where in suse by itself again some other problems are there like lan port disables by itself if suse is booted and even after reboot with windows,it doesnot work.
Is it any problem with the RAM?please help.urgent.I have work to do urgently in my computer.