Onboard graphic (vga) chip problem

hi all,

This is santhosh i have mercury (intel 845 glm chip set) mother board , i bought this one 3 years back, recently my graphic drivers giving problems, means frequently my graphic drivers are currupting , i installed somany times some times graphic drivers will be installed and some times not, if it installs after loading O/S ,suddenly system will hangup,

for this i formatted my system and i installed my graphic drivers but i am facing same thing again ,

and not only this one, my monitor also giving flickering so much, that is why

i changed display refresh rates
i replaced power cabels
i am sure no magnetic devices are near to my pc

but nothing will help me my monitor is still giving flickering

so finally i thought the problem with my on board vga chip that is why

i inserted one pci vga card to my mother board,

defaultly this vga card came up with 1MB Ram but previously my onboard vga chip having 64mb Ram

now i did n't get any flickering from my monitor but after loading of the O/S system is giving long beep and hanging up

i disabled on board vga chip from bios for avoid confilcts

but after loading O/S system is giving long beep and hanging up

i am using windows 2k and windows xp

i want to run my pc with out error and hang upS, means i am a Software Engineer so i am not bother about games i want to run development s/w in my system like DOTNET,ORACLE,SQLSERVER

my mother board is having 3 pci slots and 1 CNR Slot

so plz any one give the solution for my problem how can i over come this problem

if ur suggestion is any other vga card or AGP card (i am having pci and cnr slots only) plz give which card is suitable for my mother board

pls pls pls pls any one give the correct solution


Thanks in advance

santhosh