HP Laserjet 4000 printer problem

[MIKET]

I would like to add this problem that I am experiencing to the forum and hope for an answer. I have the above printer connected to my computer via a parallel / USB cable and the computer is an I.7, running 6 Gig Ram with Win 7 Ultimate. The problem is that I cannot print certain articles from the internet, I am a family historian and use certain sites for my research I can normally print results of searches that I carry out on certain sites without a problem, every now and then when I have been off to other sites other than those that I normally use I cannot print the page or result. If I look at the print icon shown lower right on the task bar it shows one document waiting with an error, sometimes it says Flash. Now I have Flash installed as certain sites require this for you to use their viewer and obtain printed results. I have found when this error occurs that if I turn off the computer and restart it will then automatically print the document or documents that were previously asked to print.
Someone mentioned the other day that this may be due to the Print Spooler requiring resetting or could it be a conflict with the Flash viewer software.
This has become quite a puzzle as if I do my research and stay with the usual three sites I do not appear to have a problem, it is only sometimes if I go to other sites whilst having the usual three sites open that sometimes this fault occurs.
Any help or suggestions would be gratefully appreciated.

Regards MIKET