I had problems sort of like this: I would run my Canon scanner from Acrobat and it would work for a while then the scanner software would lock up. The solution was to turn off the scanner and turn it back on. (which was a pain since each time you did that the scanner had to 'warm up' before scanning). I was ready to throw it out the window.

I finally call tech support on this and they said they sometimes see problems if the scanner is not DIRECTLY plugged into the USB port on my PC. (I had moved it a while ago to a USB hub that had it's own power).

They said that sometimes a small voltage fluctuation on the USB line would cause a loss in communication to the scanner.

I changed it and have never had a problem with it since.

A far as PC recommendations go, visit a couple of sites like www.pcworld.com or www.cnet.com for advice for PCs. They test a LOT of them and often have brief lists of 'top 10 home pcs', etc.

My PC advice (as if you asked for it): make sure you buy lots of memory (at LEAST 128 mg or 256 or 512 if you can afford it) and a fairly big (20 gig or more) and fast (7200 rpm)hard drive . Drive and memory do more to help performance than CPU speed for most people.

Good luck!

- Bob