For months, I've used Manjaro Netbook Edition on a Samsung NP-NF110 without any problems and then suddenly (perhaps some update somewhere triggered it?) I lost the ability to left-click on the trackpad. I couldn't get any help from the Manjaro forum so as last-ditch measure, I decided to re-install the OS from scratch in case that might resolve it.

Unfortunately this hasn't worked: I'm nearly always unable to left-click using the onboard trackpad button and as a process of elimination, I've used an external USB wired Microsoft mouse but it's also afflicted with the same problem.

On occasion, left-clicking with the mouse may work during a Live USB session but it usually stops working after the installation has finished and I then boot Manjaro from the hard disk. I know it's not a hardware fault because I didn't experience this issue under Windows 7.

I haven't found any leads from online searches and I'd really rather not have to return to Windows. In terms of performance, Manjaro was probably the only distro that worked really well on my netbook. Have I missed something here, can anyone offer some suggestions please? I'd really appreciate it.

A live USB session of what?

If it's a Live session of the same version of Manjaro that's installed to the HDD, I would test with some other distro, not something Arch-based, to see whether the problem is limited to Manjaro or possibly something larger.

A live session of Manjaro - the same version that was installed onto the HDD and I also tried an earlier release but it had the same issue.

I had a similar idea myself and I'm now running Linux Mint XFCE (Rebecca) and it worked fine for a few hours after the installation but now the same problem has flared up.

Edit: this link appears to offer some clues http://unix.stackexchange.com/questi...esome-wm-gnome

Intermittent problems are the most difficult to troubleshoot.

Have you looked at the log files? It's a very long shot, but there might be something useful in them, particularly /var/log/messages and /var/log/system.

Another long shot might be this: when the mouse is working properly, run dmesg and pipe the results to file. Then after the problem occurs, do the same to a different file, and then compare the files with something like diff or meled. Again, a long shot, but it might turn up something.