New
#111
The fact that there are no drivers for Win7 64 bit on Dell's webpage makes it likely that Win7 64 bit is not supported on that model Dell, sometimes for good reasons. Can you consider reinstalling with 32 bit Win7 for your version? It might solve a lot of your problems which might reappear after 64 bit reinstall and ultimately not be resolvable.
That said, you can test reinstall 64 bit to find out for sure.
Be certain that you have updated the BIOS to latest version by checking what is the latest version on Dell Support Downloads webpage for your tag. Then audit the BIOS version using Belarc Advisor, or look at System Information or in the BIOS.
If you have the latest BIOS update, then reset the CMOS. If you want to continue with RAID then keep the SATA controller setting to RAID.
If you have a working Recovery partition to return to factory Vista installation, I would consider keeping it unless you have Vista Recovery disks. After backing up my data I would then try running Recovery to see if it is still functional. IF so and you don't have disks then I would consider not wiping it so you have a path back to Vista factory installation. In that case I would just format the OS partition using installer. If not, there is nothing to lose with wiping it along with the whole HD using tutorial I linked before.
Since you are using an Upgrade version then if you wipe the HD you will need to wait to insert your Product Key until after install, doing one of the workarounds linked in my last post to activate an Upgrade clean install. If you only format the OS partition, you can give the Product Key upfront.