HP printer is not centering on labels

I have now tried to figure out what is going on. But, I GIVE UP! I have a HP 5610 OfficeJet All in One and a HP 4315V officejet all in one. The problem is showing up on both printers.
I have used HP for years! Never have I been so frustrated as I am NOW! I have Windows XP Professional.
When I try to print labels on Avery stock ( as I have done hundreds of times), I am now getting labels that are printed off center. It appears they are shifting at least 1/2 inch to the top of the stock. Therefore, cutting my labels in 1/2. PLEASE HELP ME, or I AM THROWING BOTH OF THESE PRINTERS IN THE RIVER!!!!
I am in some of a rush , to get christmas labels printed.
PLEASE HELP….Is is me, my pc, my printers????
Thanks,
Dorris