Sticky notes in 11.0.11 ridiculously slow and place signature stopped working

I used to regularly use the sticky notes feature in Acrobatto review documents, and I also used to regularly use the Place Signature feature to "sign" documents.  These features used to work absolutely fine.  However, recently, they have stopped working.  When I type text in a sticky note, it takes about 30 seconds to appear - making it completely impossible to work with.  At the same time, the Place Signature feature has completely stopped working alltogether.  Finally, I notice my laptop gets extremely hot, and battery life is about 1/4 of what it used to be.  Yesterday, I removed Acrobat and installed a fresh copy downloaded from the Adobe website.  This solved the signature problem for about 1 hour, but now it is not working again, and the sticky note feature is still unworkable.  Can anyone help please.