I noticed the same problem with PCMSERVICE.exe. I believe there was an update a couple of months ago, but it would not install on my system.  I got an error message that it was reported but have had no reply from anyone.

 

In spite of having a dual core processesor and and 2 GIGABYTES of memory, I find numerous times that my laptop slows to a crawl. I'm  sure part of the problem is due to too many programs insisting on starting up each and every time one boots up. That in addition to the firewall, anti-virus, anti-spyware, anti-spam,etc,etc that start up. 

 

I have tried removing some of this stuff, but it's hard separate the necessary from the convenient and unnecessary.

 

Also, noticing a link between MS updates and responsiveness.

The Media Direct PCMService was causing my computer to slow as well.  When typing it was ftrustrating because the cursor would delay behind the typing, then just catch up.  Dell Support could only offer the advice of a factory restore, but I didn't want to lose all my programs, so I first started up my system without the systems files or startup files.  The system files all worked fine so I just unchecked all the programs in start up and one by one loaded them until I found out which program was causing the problem.  But there was no indication that PCM Service was causing a problem in the processes Task Manager.  I believe this program was loaded as a part of a critical update I made in June from Dell.  Hope no one else is struggling with this issue.  But if your typing is delayed, sluggish, or jumpy.  Check to see if this might be your problem.  I have 2 GB RAM so even when you think you have plenty of RAM there are still programs that will slow things down.

 

Dell Inspiron 1705 running WinXP

Same exact issue as lilpreman.  Removed PCMService from startup using msconfig and my issue was fixed.  Vostros 1500 2G ram