MacBook Pro mid 2011 release keeps shutting off

i ran apple diagnostics and this is not a hardware issue.

processor is 2.4 ghz intel core i5, memory 4 GB, software 10.9.3, passed power on self test this morning. memory slots are ok.

system info says I have 254 GB out of 400 GB.

HERES WHAT I THINK THE ISSUE IS ( I am not an expert here so forgive me if I sound like an idiot) ACtivity monitor shows physical memory 4.00 GB and memory used 3.86 GB . Memory pressure full green bar. App memory 1.00 GB , file cache 1.96 GB wired memory 980.5 MB

virtual memory 4.00 GB , swap used 0.00 and 0 bytes compressed.

this MacBook Pro used to run windows parallels and when I look at the log it appears there are still pieces of that in here (I paid some apple certified place to remove that last year...the place may have been apple certified but the guy...well, let's just say he wasn't the sharpest tool...)

CPU load idle 97% , threads 499, processes 127.

IF i log on under test user (the guy set that up I guess) I don't seem to get a shut down..but When I log in under my username, it shuts down ...usually within a few minutes..last night it shut down when I tried opening ADOBE.

tthere are tons of straggling old apps...including a Citrix receiver monster of a program that I thought I had Removed ( ran a payroll from home one time)

thanks for for any help!!!