I accidentally installed the Vista ultimate business 32-bit on my dell optiplex 170l. I assumed my computer was too old to have the 64-bit. I have not been able to really find any info on if the 64-bit is compatible, but I think it is. Can I use the 64-bit disc to reinstall the vista ultimate over the 32-bit? I am having problems with screen resolution and dell has no updated drivers and i think the 32-bit is the cause to my problem. Please help!