I have no solution, but can confirm pretty much the same problem on both my Toshiba Satellite A300d Laptop and my main PC (both running PCL 2010.7). I am not skilled in Linux language and using the terminal commands, finding logs, etc and so I can't give you all the details, logs etc, and so I did not report it here, but the problem occurred each time, right after a downloading and installing a whole slew of updates that were available with Synaptic, and then rebooting. Upon rebooting, the computer (both of them) failed to find even a keyboard or mouse, much less any other peripheral devices.
The laptop would just hang and hang, with a message concerning "udev", while the PC would at least boot as far as the log in screen, but then I could go no further, as the keyboard and mouse would not respond. I even tried using non-USB input devices, and these were also not recognized.
I looked here for similar reports, but found none. Often, I don't understand the solutions being offered here anyways, as they are too technical. So, ultimately, I found no other solution, except to format and reinstall everything from scratch. But it happened again, and again, and again. I have never experienced this with earlier versions of PCLinuxOS.
What I was able to determine, is that it has something to do with updating files related to USB and "udev". I now try to avoid updates and when I do update anything, I am VERY selective, avoiding any packages that say or appear related to USB or udev. Since I started this selection process, all has been fine.
I'm sorry I can't be more helpful with details, but I do hope that this does help towards pin-pointing the problem, and identifying a good solution. It has been very aggravating, to say the least.
PC: AMD Athlon(tm) 64 X2 Dual Core Processor 5000+
Laptop: AMD Turion(tm) 64 X2 Dual Core TL-60