Mint boot problems

[koder]

I would appreciate some guidance troubleshooting a problem on my computer.

I am running Mint 17.1 on a relatively new Dell XPS i7 box.

Since I installed Mint I have been having instances of arriving at the 
login screen and the USB keyboard and mouse are not recognized.

I am not able to use the mouse to place the cursor in the login field 
for password entry.

The instances are now three or four times in succession per login session.

Every time I boot up the system goes into the GRUB boot menu and I am 
able to move the cursor around and move amongst the menu choices.

I have looked over my dmesg output for successful and unsuccessful boots 
and not received much enlightenment. They are about 950 lines of text. I 
suspect I ought not to post them.

Any suggestions?

Harold