Monitor drivers wont install

i have a compaq with windows vista home basic 32bit an i have tried every suggestion possible to install the drivers but keep getting access denied.
uninstal re-install does not work. run as admin does not work.
any other suggestions on this would be great.

also directx wont install updates something about crypogram certificates
or something to that effect.

and 1 more prob lol. ive got some games that i paid for (download)
an when i try to run them i get an error that says hardware failed to switch
to specified mode.

any an all help would be great.