My mind is working with a view to finding a solution to your problem but, I do need to ask a few further questions.
Do you have an Anti Virus Programme along with Malware protection.
If so, what are they, and have you done recent scans with them.
I could be completely on the wrong track, but I am thinking that perhaps a 'nasty' has got into your computer and, if such has, it's removal is immediately required.
Incidentally, my Desktop Computer is an HP and so is my Printer. My Laptop is now a Lenovo which has replaced a Dell which is still working well for my niece to whom I gave it.
Hans.