Cant see screen after changing resolution

I have a Dell dimension 4700 series running Microsoft Windows XP Home. I updated some drivers as I was using a wide screen however after making changes and going back to the original screen. I changed some settings on the resolutions and restarted, and now get nothing but a black screen. I get to the Dell screen and as far as the Microsoft Windows XP screen, with no luck using the F2 and F12 option. I can take the F2 to run the setup utility, that still doesn't change anything, and when the F12 option is pressed I'm not getting anywhere there as well. I know all I need to do is get to the change resolution screen in windows but the screen goes blank once started and I cant see. I have tried booting from resorces CD and that's no help, I tried all the F2 and F12 options and that does not work.
I am using the same monitor the system origanally came with, so that has not changed, is there a fix for this problem? If any one has any suggestions or maybe an idea on how to fix this problem, please help it would be greatly appreciated. I cant seem to get into the F8 option and ie safe mode? I notice now when I push the start button I get a double beep sometimes. Ive read and plagiaised other input from this site (thanks) but still could not resolove after reading their solutions. Help please.. PS I obvioulsy on another computer to do this..