I have a laptop computer that I use for travel and light weight development, a beefed up "at the time" desk top that is used for development and finances, and an older desk top that is now a Linux box that is a file server and used for Unix-like development and "enterprise server" development.
All machines had been humming along until a few months ago when the laptop started "stalling" while in use. It happened when I was surfing with Firefox so I thought that had something to do with it. But before I did anything with that, I scanned for viruses, adware, etc and it was clean.
I then upgraded Firefox and it happened on a more frequent basis. So, I went to I.E. where it happened there as well.
After doing another scan with free virus detectors and free adware detectors, it still happened.
Then it started to happen more and more. I feared a pending hardware failure and started to backup important files to new USB drives I brought just for that purpose. I stopped using the laptop as much as I had done in the past.
The other day I had to use the laptop to show examples of what I want done, to contractors who are coming to the house to give an estimate. The sleeping was happening more and more and I decided, for some unknown reason, to disable things in the "start up" tray. The first thing I did was pause Google Desktop Search.
The stalling stopped.
Later I "unpaused" Google Desktop Search and it started stalling again.
I disabled Google Desktop Search from startup and the stalling hasn't happened since.