The mint 13 default qemu (via synaptics) seems old and it doesn't seem to work. I wonder if there is a preferred repo where a working qemu could be installed?

Mint13 is old.
Get current and you'll probably get (more) current software.

I wonder if Thinkpad T42 (Pentium M) supports PAE. There seems to be contradictory info around.
And I really don't need intentionally caused HW problems.

I tried Lubuntu 14.04 (Live CD) and with "forcepae" it worked, but I'm not sure if I was just lucky after lying to the boot. I only tried if printing worked with Lubuntu. Not very extensive test drive.

I could also imagine that there could be not-so-nice consequences with lying about the HW (even if the OS worked) when using virtual machines.

BTW, Linux Mint website says: "As a general rule... unless you need to, or unless you really want to, there's no reason for you to upgrade." (http://community.linuxmint.com/tutorial/view/2)

In some pages it says that even if the flag is missing, Pentium M (Dothan) supports PAE (in which case "forcepae" is the thing to do). In some other pages they say that Pentium M doesn't support PAE.

http://ark.intel.com/products/27588/...z-400-MHz-FSB:

Physical Address Extensions 32-bit

$ grep -oi pae /proc/cpuinfo
$

system information:
-Processor-
Name : Intel(R) Pentium(R) M processor 1.70GHz
Family, model, stepping : 6, 13, 6 (Pentium III/Pentium III Xeon/Celeron)
Vendor : Intel

https://help.ubuntu.com/community/PAE:
Pentium M's of the Dothan family display the PAE flag correctly and support the latest Buntus without modifications. The same distinction (Banias versus Dothan) goes for the lower performing Celeron M processors.

Why do you care ?.
If the machine runs Mint13, what is in Mint17 that worries you ?.

How much RAM does it have ?.

I worry because I can't find the syntax of Virtualbox debugger and qemu doesn't seem to work.
Aqemu or qemu-launcher doesn't work and command line (qemu-system-1386) doesn't open Qemu-window - no console output.

It looks like something else is wrong too, telling by the behaviour seen in gdb.
With Virtualbox the guest runs fine, but I need to debug the guest.

1 GB memory.

Well: found in ubuntu forums:

I'd still rather install a working qemu than new Mint, if a working qemu can be found in some "recommended repo".