Once I re-installed Windows 3.1 because one of my program groups was gone. (It wasn't that bad; I installed the new version on top of the old version.)
Bear in mind that there was no Google or internet help forum at that time. I re-installed because it was practically the only thing I knew how to do. I did later find the "Create Program Group" option in the File menu.
I can't sync my Palm. Palm says I need a Bluetooth connection to the PC to sync; which would require me to buy new hardware for the PC so that it could receive Bluetooth signals. I have a perfectly good USB cable, which worked just fine to sync my Palm to the very same machine when it ran WinXP. (To be fair, this is less of a problem since I got a iPhone last month.)
The mouse cursor gets stuck in the top corner of one of my monitors. I have dual monitors at work, with one slightly taller than the other. As I move the cursor to the shorter monitor, sometimes my mouse gets trapped in the top corner of the taller monitor. That sort of thing shouldn't be too tricky to fix; I didn't have the same problem with the same hardware when it was WinXP.
Using the arrow keys to navigate in the File Explorer doesn't select a new folder; it just displays files from the new folder, even when the directory window has focus. This has caused me to delete the wrong folder once (which is disastrous on a network file server).
We got brand new Windows 7 installs on our work PCs about a month ago, when we switched some of our IT architecture from Widemile to Webtrends. I never used Vista, but I like Windows 7 a lot. Here are some of the things I like about Windows 7:
Shift + Right Click
You can expand the normal right-click menu for the file system by holding down Shift while you click. For instance, when you can get 'Open Command Window Here' and 'Copy as Path' by Shift + Right + Clicking a folder. It does seem a little odd to add a second modifier "Shift" on top of "Right" click, though.
My vote for the most innovative new UI feature of Windows 7 is the vastly expanded access to recent documents. Instead of being able to access only the 10 most recent documents overall from the Start Menu, each application now contains its own list of recent documents, and these can be accessed either from the application icons on the Start Menu, or by right-clicking the Task Bar. Instead of digging up the document, or launching the application and using its recent documents, you can just go to the application's icon and pick the document.
"Libraries" of documents
Back with Windows 2000, my digital life became much simpler when I finally gave in and started using the My Documents folder - a single place to store all of my documents. Windows 7 expands this concept to collections of similar media in disparate locations called "Libraries". These Libraries are indexed for faster searching, and they're all collected in a special area at the top of the File Explorer. In my Documents Library, I've got not only My Documents, but my public share drive, and the folder on the web server for all my testing. It's very convenient; much more so than the old system of keeping a bunch of shortcuts to those locations in a folder on my desktop.
Simpler window arranging
At work, I frequently compare documents to one another. I also have a rather obsessive compulsive habit of moving even non-full screen windows to perfect align with the top, bottom and sides of my monitor so as not to waste any pixels. With Windows 7, windows will stretch to full height if you drag their edges to the top or bottom of the screen. Even better, you can toss windows to the left or right side of the screen by hitting WindowsKey + LeftArrow or WindowsKey + RightArrow. Hit the Windows Key and an arrow again to move the window around the screen, or even to your other monitors.
Task Bar Window preview
I keep a pretty good amount of windows open at any one time. If you hover over an application in the Task Bar, Windows 7 shows miniature previews of all the windows you've got open for that application. This is another surprisingly handy feature.
Actually, some of these features remind me of existing features on my Macbook Air. What a coincidence.