I just purchased a computer that came with WIndows Vista. I was previously using the HP Photosmart P1000 printer with the old computer. It is not compatible with Vista so I installed another printer I had. It is a HP Photosmart C3150 and according to the Windows Vista site it is compatible. I tried to install with the CD disk and it would not download. It states it is not compatible and it directed me to the HP site to download the software and driver updates. It appeared to install it and it shows the printer as ready but it will not print. Does anyone one know what might be the problem?

HP has had some issues with printer drivers. Not long ago I saw an interim driver release there to provide limited functioning with Vista - and it promised that there would be a full release soon.

I'd suggest searching the HP site for "Vista" and your model printer to see if it turns up any significant results.

Suggestion. through the Control panel/device manger, right click your printer and uninstall the drivers. Now return to your driver CD or program:

For the printer drivers, when you get an incompatible error message such as the one you got, it usually means that you have to run the installation program in compatibility mode for XP. Right click on the executable and select properties, go to the compatibility tab and select to run in compatiblity mode for Windows XP (you may also want to run the program in elevated mode to give it access to protected areas of the registry and system files).
This has worked for me with two tough hardware problems.

Click on the Control Panel, then click on 'Printers'. Does your HP printer show up? Does it have a checkmark in a circle on it? If there are other printer icons in there, which one has the checkmark?