Hardware or software ???

I upgraded to the macOS Sierra a while back and noticed a huge slowdown in my system. I figured that since the update was relatively new I would give it time to work the kinks out. Since then things have been getting progressively worse on my system. I am pretty sure it is not a software issue, but I believe the update may have made some of my issues more noticable.

Here is my current system:
MacBook Pro 15 inch late 20111
Processor 2.2 GHz i7
4 GB ram

I was about to update my ram to the max and install a nice SSD to replace my current hard drive but before that happened a new problem cropped up.

My system occassionally locks up when it goes into sleep mode and nothing I do works short of forcing a shutdown. I have had it go into sleep with programs running and with nothing other than the OS running and I have had the same issue. It does not lock up all of the time, but when I am working on files this can be a pain.

I have no extra preventative software other than Onyx.

I did notice that the top corner of the laptop (opposite the power switch) was getting very hot and after I opened up the bottom of the laptop it is in a location far from the battery so that is no the culprit.

In order to get the system up again I have to force shut down and wait a while then start it back up. I really do not want to upgrade the system if this appears to be a hardware problem.

Any ideas for me would be appreciated.

I think it is probably well overtime for a clean install rather than the ongoing upgrades that are easier to install. This is paticularly so for MacBook of all description. 8GB memory and an SSD will make a huge difference.

Three steps to try,

Safe Mode, https://support.apple.com/en-us/HT201262
NVRAM, https://support.apple.com/en-us/HT204063
SMC, https://support.apple.com/en-us/HT201295