I've got Vista 64bit Ultimate currently installed on EIDE 400 gb HDD. I bought the W7 Professional edition, because I won't use the features of W7 Ultimate. Therefore a custom install is indicated by MSFT. Bought a 1TB WD SATA drive I disconnected the EIDE drive from computer and did a clean install of Windows 7 in SATA 1TB HDD. (works great). Problem: When I replugged the connector cables back into the EIDE drive.... My old drive is now configured as F: with all my programs and data My new drive is configured as C: Therefore, I cannot run the programs from the EIDE drive because of the changed drive designation. ---------------------------- Not quite sure where I should start. Possibly I got ahead of myself by installing the Windows 7 on the new drive and letting windows installer do it's thing. I really don't care to reinstall all the programs and data from the old IDE drive onto the new SATA drive. Entering all the serials, and waiting on the 300+gigs of applicaions and data could take days, of just sitting in front of the computer waiting on the various installers to process. I think it would be best to keep the EIDE as C: drive to access all the programs and data as I have in the past. I would definitely like to use the windows 7 pro as my operating system, but I am OK with using the Vista with the Legacy HDD apps and data. I have all the factory disks for my software so I know I can install properly, if I install applications separately onto the W7 OS. Possibly, erase,delete and reformat of the Win7 from the new disk is the answer. Maybe a dual boot is the answer. I think a dual boot would be preferred over partitioning the drive. I have had issues over time with failed partitions on the large drives. I've lost several terabytes of data in those processes. I'm not sure as I recall whether the problem was the partitioning or just a bad drive. --- regardless I lost the data. At this point I'm fishing for some suggestions. I don't like to use third party fixit/workaround tools for anything on the system. If you think a dual boot is the answer, maybe you could share alink for proper dual boot setup??