On power up the DEL key gets you into the BIOS or F12 for the boot menu.
The BIOS is an AMI BIOS. Selecting 'Product Information' showed that it was running BIOS P01-A4L (dated 12/02/2009) which is the latest one available for download from the Acer website.
In the 'Advanced BIOS Features' screen you can set up to four boot devices. With the machine booted with the SATA disk in place and a USB flash drive plugged in, the options presented to me for each of the four were:
There were also four further menu options for setting (for example) the 'Hard Disk Drive Priority'. I didn't try these out but I assume this lets you select which one you want if you have more than one of a particular type of device connected.
On power up the F12 key will bring up the boot menu. As you would expect this is just a list of devices that it finds as it powers up. In my case:
The hard disk on my R3610 had been wiped by the supplier. Acer's support site, based on my unit's serial number, told me that it had been running Linux.
In a quick look around the Acer support site, whilst some drivers were on offer, I didn't see any downloads for the original OS.
Any comments? email me. Added December 2018