Installing Windows 7 from Student Media
64-bit or 32-bit?
The bookstore will only be giving students one disk -- either 32-bit or 64-bit. Windows has been available in both 64-bit and 32-bit versions since XP. The 64-bit version makes fuller use of the capabilities of current processors, such as wider data pathways, and is able to access more memory and improve throughput performance at the CPU. One of the big differences with Windows 7 is the capability for the 64-bit version to run 32-bit programs. Previous versions of 64-bit Windows were much less compatible with the existing body of 16- and 32-bit software, and 7 seems to be able to run a larger number of Lehigh programs without a problem. Still, there may be some programs that are still unable to run under it. Users are advised to run the Windows Upgrade Advisor to check the compatibility of their software.
Do note that since all of the processors in public site machines will be capable of running the 64-bit version, and since it does provide significant performance improvements, LTS will be installing it on all of them after the end of the Spring semester in 2010, and will be gradually working to upgrade faculty and staff machines to that version.
Upgrade or "Clean Install"?
In general, there are two ways to install an operating system: either as an upgrade of the existing system, or by setting the existing system aside, and installing the new one as a "fresh" or "clean" copy. With an "upgrade" installation, one's existing registry, or catalog of existing programs and shared code, is fully maintained and automatically installed into the new operating system. This is convenient, because it saves you the bother of re-installing programs. But, errors in that catalog will be maintained, and incompatibilities between that catalog and what's needed for the new system may remain. As well, if you're switching from a significantly older operating system, an "upgrade"-type installation may not be possible. This is the case if you're upgrading from Windows XP to Windows 7 64-bit -- a clean install is required, and any other software, such as Office, iTunes, etc. will have to be re-installed.
This is why, when you put your Windows 7 64-bit DVD into a machine with XP or 32-bit Vista, a window will come up telling you that it's incompatible. Don't panic: if you read carefully, it mentions that you can boot the machine from the DVD and select "Custom" for the install type -- this provides a "clean" installation, and sets your existing programs folder and user files aside in a directory called "Windows_old". It shows the "Upgrade" option, but won't actually do the install that way -- just back up and pick "Custom".
WIRED Help
Also, don't forget that WIRED consultants can help with this -- don't be afraid to fill out the form at http://www.lehigh.edu/wired and make an appointment to meet with one. A clean install only takes about 20 minutes.