Well in response to jxvep...
If it gets to booting XP, with the bar scrolling at the bottom. It has already passed the post. The OS is also installed. Nice try but wrong. Sorry.
Kutulu take out the new card. Insert the old one. Go back into Windows. Go into the device manager.
Start>Right click on My Computer>Manage>Device MAnager
Now on the Video Display adapter right click on it and uninstall the device. You will not lose video yet. Dont worry.
Now download and run Driver Cleaner Pro
Driver Cleaner Professional download from Guru3D.com
Run that and remove all excess of your driver as well. Now shut down and put in the new card. Boot up. Should take you to Windows now easily. Once there just install the new GFX Driver.