Conversation so far:
Did something go wrong with communicating with the Spirit rover?
Communication with Spirit stopped on March 22, 2010 (sol 2208). JPL continued to attempt to regain contact and NASA announced that efforts to communicate with the unresponsive rover had ended.
Did something happen to make the Spirit rover not communicate?
It is likely that Spirit experienced a low-power fault and had turned off all sub-systems, including communication, and gone into a deep sleep, trying to recharge its batteries.
How many times did NASA try to communicate with the Spirit rover?
The timing of the 20-minute listening intervals to Spirit was not known, so multiple Sweep & Beep commands were sent. But there was no response from the rover.
Did NASA give up on the Spirit rover?
Yes, JPL continued attempts to regain contact with Spirit until May 25, 2011, when NASA announced the end of contact efforts and the completion of the mission.
What was the last thing the Spirt rover communicated?
The last communication with the Spirit rover was March 22, 2010 (sol 2208)
Did the Spirit rover send any important information?
Initial scientific results from the first phase of the Spirit mission (the 90-sol prime mission) were published in a special issue of the journal Science.
Was there any other factors that contributed to the Spirit rover communication failure besides the low power?
It is also possible that the Spirit rover had experienced a mission clock fault.

Question: Why would the mission clock fail?
Self-contained rewrite: Why would the Spirit rover have mission clock fail?