RCX firmware download problem I hope someone can help me with a problem with getting an original RCX 1.0 system working with a current PC.

I bought the RCX 1.0 system back in (I think) 2000 but its been in storage a long time. In the meantime I had children, and now one of them is curious about it and I want to encourage that.

The brick powers-up ok, but the RIS software won't install on my laptop (Win7 x64) and the laptop has no serial port to plug the IR tower into. To work around this I created a Windows XP virtual machine (in VMware Workstation), installed the RCS software on the VM, connected the IR tower to the laptop with an USB-to-serial converter, and bridged the USB port to the VM. This kind of works, in that the RIS software can recognise the RCX brick. However, it says that the firmware is missing and needs to be downloaded. When I do this I repeatedly get a download error.

Update 1: The RIS software displays the message "Initializing and downloading firmware", the LCD on the RCX counts from 0 to 20 ten times, and then the RIS software displays the error "RCX firmware failed to download". I think its trying to download from the PC to the RCS, not from the internet - if I disable the VMs network connection the it fails in exactly the same way and netstat isn't showing any network connection attempts inside the VM.

Has anyone here got a similar setup to work, or has any thoughts on what might be going wrong? Are there any command-line or diagnostic tools I could use to interrogate the RCX and/or upload the firmware outside of the RIS environment? 

I'm tempted to just buy an NXT, which will be compatible with modern hardware, but I don't feel ready to give up just yet.

Update 2: I ran a USB sniffer in the VM to view the data being sent over the usb-to-serial connector. Lots of binary data being sent to the serial tower, and some patterns that suggest message framing in an application-level protocol, but nothing I could understand that indicates an error condition. The problem is not at the level of the usb adapter though.

Update 3: In the end I found an old PC with a serial port and the RCX worked without a problem. The RIS software installs and works okay on Windows XP SP2. My thanks to those who contributed suggestions.
This did the trick for me.  My situation mirrors the original poster.  

http://neuron.eng.wayne.edu/LEGO_ROBOTICS/software_setup_tutorial.html

There are 4 parts to this.  BrickControlCenter (brickcc), a driver for the IR tower, an image of the firmware and some other piece of software called the NCQ.  

I did not install the driver since I was using a USB to RS232 adapter and BrickCC worked just fine installing the firmware.  

Added bonus, the brickCC is a full on IDE for the RCX.

Also, Swap memory has to be set to at least 4GB because of some limitation on Director 6 which causes the MindStorm program to stall sometimes as it determined that it's 3MB requirement is greater than the available gigabytes if they're 3GB or less.  Clever.